NOTE: This is an advanced, in-depth guide to Leblanc. MOST of the tactics explained will take a lot of practice to perfect. Do not be upset when you go negative for your first 10 or so games. For me, after those 10, I no longer EVER go negative save 2 or 3 times when the enemy tank-hybrid got fed too hard.

Another note is that just because you have a huge amount of kills does not mean your game is won. About 1/5 the games you dominate in will probably still be lost. This is because you cause your teammates to want to compete with you for kills after the window is open to take down weaker enemies. This is not good if they choose to do that instead of pushing turrets since you cannot.

The most important thing to remember when starting with Leblanc is that she should be played as an assassin, NOT a mage. She has one of the best burst damage in the game, but this damage is best used in cohesion with all of her utility and mobility. You cannot accomplish this when always out in the open and moving slowly.

Another warning about the skill level required to effectively play Leblanc: she HEAVILY relies on mindplay and deception (she IS called The Deceiver), and if you can't think fast, you won't master her style and are better off with her arch nemesis: Master Yi. For this reason she is not good in intermediate coop games because the bots have no reaction time and are hard to fool (i prefer taking advantage of their inability to dodge with Anivia, Nidalee and Cassiopeia).

Pros:
Very high burst
Almost impossible to chase
Very fun tricks to master
Flexible and Mobile
Master of PvP deception
Great counter to enemy assassins and mages

Cons:
Incredibly squishy
Incredibly hard to master (particularly the fun tricks)
Vulnerable to CC
Trouble taking down tanks (duh)
CANNOT PUSH
CANNOT DEFEND
Very hard to play in Coop

You need distortion first for utility in case the enemy has some tricks. It's also useful for checking bushes if you don't have clairvoyance. Also, you shouldn't even indicate to your enemy that you are interested in kills until level 6 unless under extremely favorable conditions, so don't waste mana! However, one great thing to do as Leblanc is to bruise and starve early. She has great potential to keep the enemy out of the lane, but because she doesn't have good staying power, it's a very big risk to use your spells and open yourself up to attacks. You then want your sigil since it has little burst unless you can activate its secondary. Again, use it sparingly in the beginning. Finally, get your chains for the escape potential and near-turret root potential. After that, focus on sigil, then distortion for your burst, picking up Mimic as it comes.

This section may be overly detailed ^^'...

Passive:
Mirror Image: Severely underused. Never forget to hold alt and command your clone around. This can save your butt, draw enemy ultimates and even earn you a kill when used correctly

EX: Once I was attacking a Lux at her middle lane's inner turret. We were both very low health after I threw one final sigil at her and aggroed the turret. The turret shot at me but by the time it hit I was in the jungle and my clone popped. I sent it out front to tell the Lux that I was going to try to dive. She Lasered it as the real me snuck up behind and sigiled her backside: dead.

Use your mirror image to confuse just like every other spell you use. Make it seem as real or more real than your true self. Don't use abilities while it's up until you have positional advantage.

q:
Sigil of Silence: This is your highest damage spell for single-target burst. Always mimic this unless you're trying to escape (even as you're trying to escape, if you can use mimic sigil to kill your pursuer suddenly to their surprise, that's obviously preferable to running. This happens more often than you can imagine). This is also the spell that counters the following best:

Sion and Taric can't stun (neither can anyone else, but those are the most prominent victims.
Zilean can't Ult himself awake.
Mages can't cc, nuke or anything.
Assassins will helplessly run away with no abilities to help them. Twitch and Eve can't invis and no one can do burst while they're still silenced.

w:
Distortion: This is one of the best utility spells in the game. Don't underestimate it and have enough foresight to decide when you'll need to save it. There are so many uses and they are as follows
1. Single target burst: try to always activate your first sigil with a sigil mimic, but even after that, there's another sigil sitting on the enemy's head waiting to be popped. That's when distortion comes in. If you're in range, hit them with it. This will get you close enough to then hopefully hit them with chains. If you weren't close enough to hit with distortion, it will still get you close enough to activate the sigil mimic with chains. Early game this can be used to activate your normal sigil and quickly return to your last spot to stay out of range before the silence wears off (good for anti assassin or mage in the middle. I also find Leblanc excels against Teemo even before his nerf) So early game it CAN be used as turning yourself into a projectile, but I wouldn't recommend this unless you really feel you can get an early kill this way. Otherwise you won't have enough staying power in your lane due to loss of mana.
2. Running/Chasing: Obviously, the most basic running method is to get that extra boost. Chasing is great if you have enough dexterity to get in that sigil/mimic combo afterward on a low health champ.
3. Diving: Duh. If there's a turret hugger with low hp or even a high hp squishy, jump in, sigil/mimic, and jump out.
4. Ambush: Whether the enemy is just out of reach from the bush or even better when you're on another end of a wall (i love the thing walls along the side lanes), jump in and take HP, and usually this type of tactic won't require return porting. This is the most important thing to do with Leblanc against smarter opponents who know how to avoid most ambushes. Usually they will keep an escape spell with them and as soon as they see you they will pop it. However, if you port in to get in range and then silence them, that is negated.
5. Farming: ONLY farm with this spell late game when mimic doesn't cost 100 mana. And ONLY if you are falling behind on levels or money. 80% of the time, I do well enough that all my money is from kills, and that snowballs with mejai's soulstealer. However, there is the occasional game in which kills are hard to come by (particularly games with the Twisted Fate or Teemo anti-ambush stuff) in which case don't be stingy with this one. Also use it in emergencies when there are a lot of caster minions near your turret.
6. Wall-Jumping: Leblanc can jump nearly any wall with this spell, and it's not one of those jumps that's hard to execute either. When pushing an inhibitor turret, a lot of enemies will come close to deal damage with an ultimate, then run at low health. You can destroy this tactic by then jumping the castle wall and throwing all your might on them, then quickly returning. It's happened at least 10 times where I could pick someone off like that and got a big " O.O " from my team and a " D= " from the victim. This tactic can also be used for inner turrets where you wait for a champ to come out a little bit before jumping right behind them.
7. Vanishing: This is an expert-level trick, so don't overattempt to utilize it. However, the first time you use it accidentally or reflexively, it will make your day and you'll be able to do it much more easily from that point on. This is how it's done: you are running (don't use this for other reasons. It doesn't make sense) and an enemy is chasing. You run into a bush. Distortion out of it. The enemy follows you OUT of the bush. Rewarp back into the bush. I've done this MANY times. The first effect is that the enemy wanders around for three seconds with "wtf" on their mind, particularly because Leblanc is underplayed and they don't understand her, or it just takes a bit to register what happened. This is an amazing tactic because her return port makes virtually no noise and has no animation effects. This means many enemies will dismiss it as lag or a glitch at first and continue in the direction you were running. Again, this is one of those mindplay and deception tactics mentioned in the introduction.
Note: you can also use this trick over a wall outcropping, though it is generally preferable to jump over a whole wall to escape. However, if the enemy has spells that excel in chasing, don't hesitate to try this, because all the chase power in the world won't prepare them for 3 seconds of wtf during your vanishing act.
8. Redirecting: This is also difficult, though not as incredible as the vanishing act. Running in one direction with one chaser or multiple closely-packed chasers, you can Distortion forward, wait for them to chase a bit, then rewarp and run the other way, causing at least a moment of confusion. If you can pull this off in tandem with your clone, DO IT. Two Leblancs running in opposite directions is the worst stress on ccers. This is the most common escape method I use against junglers or just anyone chasing you through the jungle (only if there are no walls to jump and you have to escape immediately) and therefore the leading cause of death for Leblanc is a jungle swarm (that and bush parties of 3-5 GET CLAIRVOYANCE) because she needs the enemies to be single or all clustered together to fool them. It doesn't help to escape from one only to run into another with all your abilities on cooldown. The person to figure out how to get out of that situation with ANY character will probably have a kill-death ratio of 10-1 or more every game (don't worry. once you master this build that will be commonplace if not every game anyway)
9. Sucker Shackle: This isn't the most amazing tactic, but I realize the merit versus short range characters or skillshot mages. The idea is that after all your abilities are used except distortion and chains, you distortion the enemy's face and chain or vise versa depending on the situation. Then you rewarp and watch them sit there helplessly getting chained as you fire your refreshed sigil at them. It's basic, but still worthy of mentioning. Use this when you're having trouble with enemies escaping.

e:
Ethereal Chains: This is another great utility spell. It can be used for its damage, its slow and its snare. Use it to escape for an easy hit or to initiate a bush fight after using Clairvoyance to pinpoint the placing. Note that you can't use this spell to chase very well as it only reaches the furthest point you indicated first, not growing longer as you move forward, so it can't reach fleeing enemies unless you're practically breathing down their necks already anyway. Use it in that situation anyway. Pretty much use this spell for initiation on tougher targets when you have no element of surprise to utilize or to finish low targets when all other abilities are on cooldown. Don't be stingy with it. It's low mana cost, relatively low cooldown and is never a bad idea to use (just don't get yourself killed in the process of trying to get close to use it). Also, when you successfully chain a fleeing enemy, don't sit there shooting at him (i mean with autoattack. If you have sigil, use it). Now's your chance to gain ground on him and either cut off his escape or sandwich him between you and your friends lagging in the back. Once you're in front throw your newly cooled spells at him. Hopefully he was low enough health to kill at that point but if not that means you shouldn't have tried to chase him in the first place.

r:
Mimic: Straightforward enough, this is what makes Leblanc so versatile. Whether it's escaping with a double Distortion or single-nuking with double sigil, use it without mercy and don't forget that if it's off cooldown that means you can always turn around and fire two sigils in a chaser's face which is preferable to escape. You almost never want to double chain, though unless playing against an INCREDIBLE tank. Almost all situations call for more of your envied burst from sigil, however.

Don't be stingy with mimic. If you are confident there is no danger of a counter to your ambush (a sleeping gank), just mimic sigil on them. Its range is long enough that you should not have to worry about retribution before running away.

If you are particularly skilled in maneuvering the jungle, always try to show up behind the enemy pushing your turret. This negates the need to Distortion in, and allows you to simply walk up (or run as it were with boots of mobility) and throw both sigils while the enemy must make a choice between running toward you (aka no need to close distance with Distortion) or run into the turret (not likely). You can then conserve your Distortion for burst on them.

Your Mimic is your highest cooldown, but it is only 30 seconds or so. This is great for hit and runs. Your Mimic cooldown entirely dictates why you should wander and not lane forever or teamfight too much. If a fight is going badly, the only thing you can do to help while your mimic is on cooldown is to chain. If that's on cooldown too, don't try to save your friend. You're too squishy and one death will quickly turn into two if you try to be too heroic. This will earn you a lot of scorn for people that don't understand the concept of no AD and high burst/high cooldowns, but it's better than losing charges on your Mejai's Soulstealer.

Clarity: For early game this is great for if your enemy is aggressive or if you yourself wish to be aggressive (middle lane) or if you're in a side lane (you will need to use spells early game in the side lanes). If you're on a roll and you are taking down people quickly without taking damage (which is about 70% of the time as Leblanc) You will like this spell for getting to the next person without having to blue pill as much (you will still have to a lot as Leblanc). Don't be stingy with your mana after lvl 6 ON CHAMPS. Don't waste mana or cooldown distortioning minions as it's high cooldown and your best escape or chase tool. Without it, a gank will get you good (smart enemies will wait until you've used it to attack).

Clairvoyance: The most severely underrated summoner spell in the game, this is great for ANY skillshot snipe like Anivia or Nidalee, but it is also incredibly important for Leblanc. The number one cause of my deaths as Leblanc is jungle encounters. While you are one of the best jungle navigators, walking into a bush of cc and melee damage is not good for your low HP. Also, if you are relatively certain there is an enemy in a bush, pop this incredibly low cd spell on them and throw chains in their face to initiate a great surprise counter combo.

Others:

Cleanse: A possibility. I don't like it because I'm careful about getting into places with high cc and you have your silence to negate that.

Flash: You can see the merit in teleporting a huge distance to assassinate, but its cooldown is not worth it to me when you can already do so well with your distortion.

Ghost: I used to use this, but the thing is you already move fast and have great escape. You won't usually have a problem escaping unless you are cced in which case ghost can't help you.

Ignite: I never use ignite as people tend to get away with low HP just as often using this as they do without. For Leblanc, if you can't kill someone in 2 seconds, you almost never want to stick around to discover what counters they have for you.

Teleport: Good for learning a champ, but not for once they're mastered. You will get Boots of Mobility, period. Your blue pill is going to need using way more than this cooldown can handle, so just stick with high movement to get around.

Never:
Exhaust: There's no point because again you use all your abilities in burst so if they're not dead in 2 seconds or have low enough health that you can follow them for one more sigil, just leave or chain them to the ground for an assist.

Fortify: Champs that are good at pushing are often the ones that are good at defending a turret. Leblanc can't do either due to her cooldowns and squishiness. Most assassins are like this.

Heal: You are that squishy that heal won't EVER save you.

Rally: You don't use AD

Smite: You don't jungle creeps (you jungle champs ;) )

Revive: I'd have to agree with the general consensus that this is the worst summoner spell. It's not the worst thing to be missing Leblanc for half a minute as it is for if a tank, support or carry died. In fact, it resets your mia status which is the most important thing for assassins.

Straightforward. Mpen is obvious, and take utility that compliments your summoner spells. Take as much Mana Regen as possible (in case you do well). And if you foresee doing REALLY well, take Utility Mastery for getting blue buff. If you want to play safe, take what you see.

This is relatively a loose guide to your runes depending on whether or not you want early game domination or a snowball effect (which is probably the better idea). When I started playing Leblanc I read a guide that said "she has a problem mid and late game" so naturally I added Mejai's Soulstealer and Rod of Ages to my build quickly and stuck growth runes all over her. Luckily I discovered later that all assassins have late game problems if they are not fed correctly. Very few assassins including Leblanc with all her Distortion might can farm decently.

The gist of it is that Leblanc's early gameplay is already just fine, and as I'll explain later, you won't need huge HP or Mana or Mana Regeneration early (or even later depending on your style)

The most important thing when learning a new champ is to decide which stats are incredibly useful, which stats are necessary even though they don't carry too much bang, and which stats are relatively useless. Obviously, you want assassin/mage stats as opposed to tank/carry stats, but what stats that other assassin/mage champs take will not be useful on our little Bundle of Lies? More on this in the items chapter...

Marks:
Overall, MPen is necessary for every AP Assassin with burst (Leblanc) and every offensive mage (Leblanc is not a mage, but there it is).

Seals:
Mana Regen is not important to Leblanc, but try doing without it and it's a pain. Leblanc already has to blue pill a lot, but I'd get these over HP for reasons explained in items later. Here of course is where you can deviate significantly. If you want more HP I wouldn't necessarily think that was a bad idea.

Glyphs:
AP/lvl is sort of exchangeable for Flat AP, but like I said, Leblanc is good early game no matter what, but as a squishy you should focus on defensive play till at least level 6 anyway. This is where per levels often start to catch up anyway, so think about this before you make your decision.

Quintessences:
This is the most flexible part. Generally, I like to go for as much AP as possible for endgame, but other quints that could really help are flat ap, movement and hp (for more magey Leblanc).

Prologue to Items: In order to understand the item build, pay attention to the needs of the champ. What stats do you need? If you can answer that question and you are knowledgeable toward the items, you can probably go out and make the build I have below without looking at it, or else something to suit your own style. As it is, let me tell you what to look for, those who aren't sure. The needs are on a scale of 0-5

HP 3 a bit of survivability so AOEs and DOTs don't kill you (death by mushroom is embarassing)
Mana 3 yes this is as needed as HP because of your MP5 runes. Frequent burst is what this champ does. Large mana pools won't be necessary. That's for mages. You Blue Pill a lot anyway and with Boots of Mobility that doesn't hurt too much. Rod of Ages gives you more mana than you need already.
HP5 0 same reason as mana above
MP5 0 no reason to get this as long as you got the runes.
AP 5 burst damage with high scaling. aw yea.
AD 0 only autoattack when they have 5 HP.
Crit 0
APen 0
MPen 4 you can't take down tanks unless you have this or you're incredibly fed.
MV 4 take boots of mobility. It's a must. Lich Bane is a maybe.
Arm 1 only in those RARE cases should you get a thornmail.
Res 3 Leblanc can escape most autoattacks, but spells are a pain, particularly stuns.
Dodge 1 if you want to there's nothing wrong with it, it's just what are you sacrificing?


This is another hard part to explain. The thing with Leblanc as I've said before is she is a terrible farmer. Your money is short, and this is why you shouldn't get a Doran's Ring. Also, the Health Potions are far too important to simply not have. Clarity will help you stay in your lane early and the Health Potions compliment that particularly in cases where you are forced to be more aggressive. I get the boots because it is unlikely you will get kills too early, but your early spells are strong enough that they don't need boosts, and by the time you are level 6 you will probably only have money for Boots of Mobility and one other thing. Leblanc is terrible without mobility so nab this first. Also, once you are level 6 unless you have the ability to stay in the lane for much longer, it's time to start killing. Almost always I am able to lull the other person in mid into a false sense of security as I focus on minions before 6 and then once I have mimic I destroy them. However, the main idea is that the boots allow you to show up in random places much more easily. Like I've said before, Leblanc NEEDS ambush. The more you are mia, the more effective you are. This is true for EVERY assassin. Learn the jungle and never be predictable. Travel to areas where there's a low health enemy or a single bold one. Pick off squishies. Everything. DO NOT stay in a lane too long. You're NOT a mage.

The next thing you want is Mejai's Soulstealer if you have experience with Leblanc. I almost never have trouble getting stacks because if you know how to play her you WILL get kills and you will almost always come out positive. This item is crucial. Don't neglect it. Even if your team is doing well, you must realize that Leblanc will not do well unless she gains a snowball effect. If you end up getting no stacks, don't be upset that you bought it. Other items would probably not have helped you do better.

Third you want Rod of Ages. This item is also crucial because it gives you survivability which every assassin needs. In fact, I think every AP assassin or mage needs one of the HP/AP hybrid items (Rod of Ages, Rylai's Crystal Scepter, etc). Banshee's Veil is great but if you're not getting AP at the same time, you're like a large, muscular impotent man (no offense, guys). Now this item shouldn't mean you consider yourself invincible, nor should you attempt to get a whole lot of other items that increase survivability. Like I've said before, Leblanc relies on utility for survivability. If you waste your money on HP, you'll lose your burst, which is the one useful aspect of this character to your team. However, This is the only early survivable item I would take (later you can get a Banshee's Veil) because it helps you have a larger window for knowing when to escape and makes you in between the very squishies and normals. You will never be nonsquishy without sacrificing core components of your champ, but this item is still a must in early to mid game where your abilities are still dominantly powerful to not need straight AP yet it helps your snowball along for late game when you really need extra help. The idea with this item is countering Leblanc's squishiness and late game needs. On that note, DON'T waste your time on Rylai's Crystal Scepter. It gives similar stats, but weaker, and the spell slow will NOT be useful for Leblanc (believe me, I've tried). Your spells will either kill instantaneously or...not. If not, Rylai's won't help you. Your spells are all on cooldown. Are you going to follow for 15 or so seconds waiting for Distortion? You also have Ethereal Chains which is not going to benefit from Rylai's but it reduces the merit in it. Make up for what you are missing in slow effects in your own dexterity and power. Better they're dead than slowed.

Once you get to this point in the build there is a lot more room for wiggling around. I very often deviate from the build once I have my core Mejai's Soulstealer, Rod of Ages, and Boots of Mobility. Rabadon's Deathcap is most often the next item I take, though the Void Staff and Banshee's Veil are viable as well. Note that if you're dying more than you'd like, Rabadon should be out the window. Get Banshee's Veil. If you aren't dying but can't seem to kill anything and are getting starved, take the Void Staff. Rabadon is only worth its money if the Banshee won't save your life and there are no Banshees or Angels on the field AND if your Mejai's Soulstealer is stacking. The idea is that in a long game it doesn't matter much if you are getting Rabadon early or late, just that you get it when you have Soulstealer stacks and when the Banshee can be correctly positioned in the game timeline. So only take Rabadon if you already have a significant snowball, take Banshee if you're melting, and take Void if you're stagnant.

Viable Options:
Lich Bane: I don't like it. The mana is unnecessary, the activation requires you to stay longer than you may want to...but the movement speed is nice and extra AP is great. Definitely a style-influenced item.
Morello's Evil Tome: I get this ONLY when I'm doing INCREDIBLY well instead of the Void Staff. You can even get it before Rabadon's Deathcap if you're doing that well. This ensures that if you're on a roll and have plenty of feed early game that the feed comes faster and inevitably keeps coming. However, It won't earn you kills if you're not already getting them.
Thornmail: Okay this is HIGHLY situational. Only if there's a fed enemy carry should you even think of this. And only if you are not able to kill them instantly. AND even then the Banshee may be preferable. Think long and hard about it because in the end the only reason you would buy this means you're probably losing anyway and there's little Leblanc can do to turn an entire game around.

Tempting Items to stay away from:
Abyssal Scepter: If you need Res, take a Banshee, don't try to help your team. Odds are you're not around them much and you want to stay a good distance from your target if possible. The best way for Leblanc to help a team is from the shadows, lurking and making enemies cautious about pushing.
Archangel's Staff: It's a mage item. A staying item. You're not a mage. You don't need more MP5 than the runes give and you don't need huge mana because odds are you're going to lose HP and have to recall anyway, and you don't WANT to "stay". Stick to the universal "mia scare" and don't try to stay in the field where enemies can predict your location too long.
Rylai's Crystal Scepter: Explained in the Rod of Ages section.
Zhonya's Hourglass: The armor is unneeded and you should try to escape, not stay and try to survive.
Sorcerer's Shoes: Are you a mage? No. You can't move across the map in these in any good amount of time.

I'm open to suggestions. Things like Shurelya's Reverie might be worth mentioning but I never tried that one on Leblanc before. Let me know!

Early Game
This is the biggest variation in Leblanc playstyle. I know I've said don't play as a mage, but set her up in the beginning as though she were a mage. This means don't engage in the middle and in the partner lanes reserve your mana until level 6. Don't farm with Distortion. Wait for the opportunity to strike enemy champs (autoattack them until your partner damages them enough for you to do a death combo). Nuke your whole spellset at them when the opportunity arises after you have Mimic. Don't forget. Leblanc is all about deception, and your best long-term deception comes from pretending to be a mage then surprising them with a big nuke as well as pretending that all you care about is last-hitting minions. Pull this beginning off correctly and you will get your snowball started very effectively. In the middle early game can last until level 10, but after that you REALLY want to start roaming. The end of your Early Game should be very defined. It's the first time you A. bruise the enemy out, B. kill them, C. get bruised out, D. die, or E. can't make take any ground up till level 8-10. Note this is all after level 6. At this point you should have enough money to get your boots of mobility and that's exactly what you should do. This gives you your first and freest disappearing act because up to this point your lane adversary(ies) will think you are playing as a mage and will soon return to the lane. Your boots of mobility will not give them any chance to even think you are mia and before they know it mid is being ganked or the other lane's low HP champ has been picked off.

Mid Game
This is the part where you really shine as Leblanc, or set yourself up to be truly brilliant late game as it were. You are now working to maximize Mejai's Soulstealer and you have a growing Rod of Ages. At this point the enemies still don't realize they should watch out for anywhere their LOS does not hit. Take out anyone you foresee being a problem late game to gimp them (any assassins, mage nukers, carries). Also look for opportunities to gank the heavies against whom you will have much trouble alone against until late game if you do well (Sion, Taric, etc.) I can't stress how important it is to stay off the enemy's minimap, and that's why it's so important to gimp Teemo and Twisted Fate. Their abilities are so anti-jungle and anti-ambush it's crazy. For fighting enemy junglers don't forget the clairvoyance. Don't expect to go with no deaths very often with this build, for while Leblanc is one of the best escapers, playing her well requires a great deal of risk that mages don't need to subject themselves to.

Late Game
You definitely know now whether your snowball built or melt at this point, depending on whether or not your level kept up, how many stacks you have on Mejai's, how long you've had your Rod of Ages and how many per level runes you took. If you have it all, you've not only negated Leblanc's late game problems, you've risen way above it. The reason she has such "problems" late game is because she now has to deal with banshees, high resistance tanks, high damage carries and the general enemy knowledge of her play style. Late game is when unless they are incredibly dumb the enemies will start team pushing instead of letting themselves be picked off one by one. The thing is, if you were fed enough, it doesn't matter anymore. You can take out any squishy instantly and negate one enemy in a team fight. Make this a support who neglected resistance and HP, a mage who did the same, or best of all, an assassin so the shadows belong to you. No matter what, someone will always stray too far from the team, trying to stay safe in the back or chase in the front. Those are easily picked off by you, since you have the ultimate positioning power. However, if you did not succeed in snowballing, now is the time to behave more mage-like. Farm minions with Distortion and Mimic (which should now cost 50 or no mana), and stay with your team to warp in and pick off a low health champ. In essence, this is where you are trying to pick up your snowball again. Play safe and stay away from the jungle if Shaco or Warwick (or any other roamer) has been fed.

Champs to watch out for:
Master Yi (for anyone, but he can annihilate you if you failed to take him down and used up your Distortion escape)
Teemo (you have the ability to ruin him, but he has just as much ability to ruin you)
Anivia (deceptively hard to kill)
Nocturne (spell block)
Sion (stun, always)
Warwick (jungle master and good chaser)
Shaco (jungler and his clone beats yours any day. he also relies on snowballing like any assassin, but moreso him and Leblanc than others)
Twisted Fate (ruins your ambush)
Nidalee (trap and spear combo could potentially one-shot you at halfish health since you're that squishy)
Taric (stronger than most healers, can stun and last through plenty punishment, making him anti-gank)
Morgana (never actually had a problem with her, but if she is skilled she could potentially turn around and get her anti-gank off on you before your gank lands
Cassiopeia (just as Leblanc is the master of ambush, Cass is the master of traps. Don't ever follow her unless it's obvious she's bluffing. she can and will ult you alone if you're doing well)
Cho'gath (never get too close or you'll seriously regret it. also nearly impossible to kill alone)

Situations:
Banshees: The wonderful thing is you have a 4-sec cd sigil. always use it to get rid of banshees for your team, but don't shove off your combo until that sigil is back up.
Angels: getting your ethereal chains ready is the best counter for this.
Team not pushing in a game dominated by you: Stop roaming and stay in a lane (but be cautious). This will draw the enemies to you and force a team fight, meaning your teammates actually show up and if you win you get to push. If you don't then it's not like you would have won with zero pushing.
Twitch and Evelynn: Once you are experienced these champs should be easy prey and you should be good at dying VERY little. If you die rarely, an oracle is your responsibility. As the assassin, the enemy team's assassin is your job to keep in the spawning pool.
Enemy Leblanc who also read this guide: Well...sorry, you're out of luck. No guide is perfect.

I recommend the Wicked Leblanc skin to anyone who really enjoys her. Cruella Deville does not get enough attention these days.

Also, if you would like me to, I will post some screenshots of games I've played with Leblanc. I will even post pictures of games I lost with a positive score (as they come). I know It's a long guide, guys, but I always wished for more in-depth guides for all those hard champions, so here's mine. Comment and give me your feedback. I'm always looking to do better as this awesome character!