Hi,
This is my first guide here, and i wanna show you how I play Katarina.
First of all, this guide was made for Blind Pick games primarily, but it will probably work on Ranked games aswell.
This guide isn't intended to be the best Katarina guide on Mobafire, but a useful guide wich can be checked every once in a while.
Katarina is a melee champion without mana that can build both, attack damage or ability power items. I'll focus more on AP because I've had more sucess this way, but it depends on playstyle.
Also keep in mind that the guide is based on solo mid as Katarina. You may need to do some changes to play other lanes.

So yeah, I'll try to write a short and useful guide, hope you like it.

Updated 3 July.

Pros:
No mana (go ahead and spam your Bouncing Blades, it's free!!)
Has an escape mechanism ( Shunpo)
Area of Effect (AoE) Ultimate (up to 3 targets only will receive full damage)
GREAT passive that makes you GREAT at team fights

Cons:
Squishy early game
Needs a defensive early game (in most cases)
May miss some CS (due to cooldown on Bouncing Blades)
Ultimate easily interrupted
One of the first targets on team fights

My Rune choices are kinda standard to mid champions with a few modifications if you prefer to lane with a friend. Keep in mind that runes are a personal choice, I'll show all that may work on Katarina, it's up to you to choose wich ones you will use.

Quintessences:
Greater Quintessence of Ability Power will help you with some early game damage, boosting your initial AP by 15 points.
Greater Quintessence of Movement Speed is your second option. You get really mad if they arerunning and you can't Shunpo them? These may help.
Greater Quintessence of Health is your quintessence if you wanna have some more hp by early game. I just don't think it's needed, since we got Veteran's Scars .

Marks:
Greater Mark of Magic Penetration will boost your damage through the entire game, with Sorcerer's Shoes and you Mastery, you will be doing true damage to champions that didnt buy any Magic Resistance. There's nothing nearly as good for marks.

Seals:
Greater Seal of Armor is a good choice since we won't be buying armor early.
Greater Seal of Health is your next choice if you feel better with them. I just prefer armor.

Glyphs:
Greater Glyph of Scaling Magic Resist is your better choice to negate some of the magic damage you will receive by mid game, when your mid oponents have enough mana to spam some abilities.
Greater Glyph of Cooldown Reduction is chosen if you wanna excel at 1v1 combats, thought they lose much of their value on team fights.

My masteries are standard also, 21/9/0, To boost some of your early game Surviability and Damage, since you won't really need increased neutral buff duration (ok, grab it sometimes, but you know that there are people on your team who will really excel with them).

Q: DAFUQ why no Havoc ?
A: I prefer to have 1 more attack damage than 0.5% more total damage, since it will boost your early game. Anyway 1.5% extra damage isn't really needed if if you did a good early game.

You can run with defense masteries, grabbing Arcane Knowledge in offense. An utility build is also possible, but not recommended. Also, it is possible to get no points in Mental Force and grab Havoc . Again, it's personal.

The skill sequence showed on the build is based on early game farming and mid game domination. It can also be changed, but i won't recommend leaving Bouncing Blades at level 1, you can farm really well with it, and it's up to you to leave it level 2 or 3.
In that sequence, you are supposed to dominate your oponent by level 11, when you get level 5 Shunpo and level 2 Death Lotus.
Other thing that can be changed is delaying Preparation to level 13, wich you can do when your oponents don't have Heal, nor any healing abilities. If you can't live without the damage reduction when it is used with Shunpo, sure, grab it at level 4. Again, it's personal.

My golden rule says Flash or Ghost is nice for most champion, and for carries, AD choose Exhaust and AP choose Ignite. So you can combine them. The fact is that Exhaust synergizes so well with Death Lotus. So I choose Flash and Exhaust. You can always change Flash for Ghost and Exhaust for Ignite, the most important thing is that you keep one offensive spell and one defensive (this rule won't apply if you wanna get Heal, wich you should put in the place of Exhaust or Ignite.

You should always start with Boots and 3 health potions, because the probability that you will have to dodge something in early game is high and you need the potions to sustain your game and farm better. If you feel confident you can always start with an Amplifying Tome and a potion, but i won't recommend it.
Your next purchase is Hextech Revolver wich will give you sustain to, once again, farm better.
From here, you will begin to build offensive items. You can choose what you will buy between 3 choices:
Sorcerer's Shoes;
Hextech Gunblade; or
Rylai's Crystal Scepter.

It is always recommended to build the Sorcerer's Shoes in between one of the other choices, but most cases what will determine the item you will buy is the amount of money you have when you recall. Always buy the most expensive item you can afford.
Hextech Gunblade will give you the burst to grab a kill if your oponent can't Flash out of the slow. It also works great with Death Lotus.
Rylai's Crystal Scepter works great to maintain the pressure on the oponent. Actually, at Blind Pick games, i have seen some people just flash out after my Shunpo, even though i didn't use Death Lotus.

Q: But you already have a slow from Rylai's, why do you need the Gunblade?
A: Countless times my gunblade has secured a kill and countless times my Rylai's have secured my way out of a team fight. I highly recommend using both since both synergize so well with your ultimate.

Your next item will make you a killing machine, Rabadon's Deathcap. It will just increase so much your AP it is ridiculous.

Then there comes the defensive items. In the build, i suggested Abyssal Mask and Zhonya's Hourglass, if you are not having problems with AP champions or if someone else got Abyssal Mask, you can buy Lich Bane. Use your common sense and buy the Magic Resist item first if you are having a hard time with AP champions or the Armor item if you are having a hard time with AD champions. If you are doing great, just buy the Needlessly Large Rods before.

If your oponents are starting to build a lot of Magic Resistance, you should buy Void Staff instead of one of the defensive items. If you think that having no item for armor or MR is really bad, Guardian Angel is always there.
On a late game scenary, you may want to even change your boots, because flat spell penetration won't really help. CDR, Speed 3 or Tenacity are the best options. I'd stick with the tenacity.

Will of the Ancients is a really nice item, if the enemy lacks CC. After your first burst, you should still be full hp or near it, so having more spell vamp won't help you burst higher or survive longer. I see a lot of Katarina's that buy it before Hextech Gunblade, or even don't buy the gunblade at all. Well, i guess its ok to change the Gunblade for WotA if you can't stand items that you need to use.

Deathfire Grasp can be a great help with burst damage, but i found its CDR kinda wasted. Its another personal choice here. If you wanna buy it, i strongly recommend running Flash/ Ignite and buying it after Hextech Gunblade, so you have its surviability and burst.

As you may have noticed, your early game is dedicated to farm. Farm. Farm. Farm a lot. Harass your oponent when he makes a mistake (all offensive spells on cooldown, lane way too pushed, and others), but be sure to deal more damage to him than he can deal to you. That means don't Shunpo to them every time, they can hit your harder on your way back.
Surely, you can try to grab a kill, but it isn't worth if it means risking your life. Pay attention to ganks from the jungle/other lanes. Something you can do about gankas is buy one ward and put it on the brush by the river. Once you're near it, you're safe. Avoid warding all around you because it will delay your items.

tl;dr
Farm a lot and don't risk your life.

You can be a bit more aggressive here, as you have more points on Shunpo. If your oponent dies or recalls, push your lane and jungle a bit, don't attack their turret too long or someone will surely gank you. You will need the money. Much money. Really much money. You will need to judge by yourself when its better to jungle or to attack a turret, or even to gank another lane. Remember that you can Shunpo out of a gank to one of your caster minions.
When you go for the kills, wait for them to use their stuns, else they will just stop your Death Lotus. The following sequence usually works very nice, be it a gank or a face-to-face attack.
Bouncing Blades > Hextech Gunblade > Shunpo > Death Lotus
Remember to cancel your Death Lotus when they go out of its range to Shunpo them as soon as possible.

tl;dr
Don't stop farming while you try some kills.

Late game is where you shine. If you could farm nicely enough, you will be dealing tons of damage even when you just Shunpo > Bouncing Blades. Now gank is the word for you. Gank as much as possible. Push turrets after. You may get red or blue buff, but i'd rather help someone else get them. On thougher oponents, you should use the same sequence as above. Its a pretty huge nuke.

Team work is very, Very, VERY important for Katarina, once you won't find many decent teams without a bunch of stuns, knockbacks and things that can interrupt your ultimate. It's highly recommended that you play Katarina along with at least one AoE CC champion, such as:
Amumu
Alistar
Blitzcrank
Galio
Malphite
Morgana (If she can land it)
Sejuani
Sona
Wukong

Some other Champions with single target CCs may also work, but these are the best. If there is a Morgana on your team and her ultimate is on cooldown, you can also ask for a Black Shield, it will help wonders.

So you're probably going mid, but you will fight any champion by late game, so you need to know a bit about every champion. I'll list only the abilities you have to actually worry about, so it will be quick. It's based on my own experience so you may find more skilled players than i did.

Ahri has a taunt, Charm, make her miss it. Everytime. She has skillshots, make her miss them. Attack her only after she uses Charm. Remember that Shunpo can dodge Orb of Deception, and if you move a bit in her direction it will also dodge its way back.

Akali is pretty much like you, but a bit more agressive. If she can mark you with Mark of the Assassin], dont let her touch you. If she has [[Shadow Dance (aka ult), she will go for the proc on the mark. If you have more hp than her, you can just Shunpo > Death Lotus. Remember that she has a decent burst too, so do your math.

Alistar can't do much damage, but has a ****load of surviability and CC. Only ult him if he just used his 2 CC's, Headbutt and Pulverize. Keep using Shunpo and Bouncing Blades untill he gets tired of it and goes base.

Amumu is a tough tank, but has only 1 normal ability that can interrupt your ultimate in a fair cooldown, that is Bandage Toss. His ultimate will stun you, so, if team fight'ing, wait for him to ult before you do.

Anivia is a funny bird to lane against. Her main damage ability on levels 1~5 is a skillshot. So, if you see it, either, you are in range to Shunpo Articuno or you can easily avoid it. When she gets ult, wait until she uses it and jump on her. Within some deaths, she will probably start ulting the area she is, just trow a knife and walk away.

Annie is a great problem. She will farm without spending mana and land an easy combo that will take a lot of her mana away. Her main nuke is Disintegrate, wich has a short cooldown, so when you see her using it on a minion to last hit, Shunpo her and trow a Bouncing Blades. Retreat fast. Remember that if she Incinerates you, its your advantage, since it will deal low damage and take away a nice chunk of her mana.

Ashe will have a great advantage in early levels. She will zone you so much its disgusting. If you trow her a Bouncing Blades her auto attacks will deal much more damage. Just farm until you turn 6. At this moment wait for her to try to ult you and dodge it with Shunpo on her or to a minion. Then you are free to ult her in the face.

Blitzcrank: seriously, don't try to fight this guy alone if you aren't way too fed. Chances are that he will Rocket Grab you, knock you in the air and a bunch of his friends will scome to finish the job. If nobody is near and you wanna chase him, he will just silence your Death Lotus with his ultimate.

Brand: Shunpo to wherever when you see his Pillar of Flame. You should be fine.

Caitlyn: A bit worse than Ashe, you can't dodge her ultimate (at least i never tried). Don't try to go back with low hp when she has ult, or you are dead meat. Care for her traps because they make it even easier for her to kill you. Just farm a lot and ask for some ganks to send her back to her base.

Cassiopeia will poison you to death. Don't allow yourself to be hit by her 2 poisons, or she will deal too much damage, stay back and Shunpo when you see a poison incoming. Her ult may cancel yours, so try to walk a bit away from her before ulting, she won't even notice.

Cho'Gath is another pain to fight. Pretty much the same thing as Alistar, but he can deal more damage.

Corki: staying behind minions is essential to dodge his Missile Barrage. Other than that, not a great laner. You may wait till he uses Valkyrie to use Death Lotus, or it will cause you to scream "SON OF A BEACH!" IRL. True Story.

Darius can pull you to him with Apprehend, cancelling your ultimate. If you have to fight him, don't do it alone. He is a monster and can win trades even if 2v1. His Apprenhed is in a cone, so try to stay away from teamates.

Dr. Mundo is a nice guy, whoses Infected Bonesaws can be dodged by Shunpo and whose Maximum Dosage may be reduced by Preparation > Bouncing Blades. one of the few tanks you may try to fight.

Draven is a great runner with his Blood Rush, be sure to ult him only when you have some kind of slow available (gunblade or exhaust, for example). Stand Aside will also cancel your ultimate, take in account its 18~14 sec cooldown and time it right.

Evelynn is a stealthed roamer. If she gets you low you are dead meat. If she gets you at medium health, well, she can't stop your ultimate, so it may be worth to try. Start with the ultimate this time so if she chooses to run away you can Shunpo and Bouncing Blades her arse. You can even buy a Vision Ward and keep it. If she stealths on low hp you can try to find her.

Ezreal is a single word for you. DODGE. Dodge everything he trows at you and when he gets mad and use Arcane Shift to attack, retaliate with you basic skill combo.

Fiddlesticks is another problem. You can't stop his Bountiful Harvest and he can stop your ultimate in TWO ways. Well, if he uses Bountiful Harvest on a minion to regain health you can retaliate, but a good Fiddle will fear you out of him and walk away. The only good thing you can do is Shunpo to some nearby minion if he catches you on Bountiful Harvest. To effectivelly attack, wait untill he's low on mana.

Fiora is not a big deal when she's not fed. Her ultimate, Blade Waltz has way too much cooldown to be a reliable escape mechanism from your ult.

Fizz isn't a big deal either. Just wait to combo him after he jumps away from one of your Bouncing Blades > Shunpo mini combos. Be sure, thought, to not ult while he marked you with his ult (a little fish "swimming" around you).

Galio can resist your hits and retaliate well. He's a dangerous laner and team fighter for you. Ask you AD carry to take him out. If that's not possible, well, you can still dodge Resolute Smite with Shunpo like any skill shot.

Gangplank Has no way to stop your ult, but he can Remove Scurvy his way out of your slows. If laning against him, retaliate his Parrrley shots with Shunpo and Bouncing Blades and go out asap.

Garen is a tough early game champion. Bouncing Blades him constantly and Shunpo somewhere near when he uses his Decisive Strike to reach you. Care for his ult, he can kill you with Demacian Justice if you are low on health.

Gragas trowsa barrel at you. You Shunpo to Gragas. Don't let the barrels hit you and you will be pretty much fine.

Graves is pretty much like Ashe on laning phase. On my opinion he's worse than Ashe at late game, so not a great problem.

Hecarim can cancel your ultimate with his Devastating Charge. Other than that, don't stay fighting for much time near him.

Heimerdinger has no way to stop your ultimate. Against you, his turrets are a double-edged sword, once you can Shunpo them and then reach him.

Irelia Has a nice lifesteal, so constantly use Preparation along with Bouncing Blades to cut it by a bit. Don't try to fight her 1v1 without your full combo.

Janna is a support champion that will trow you a mile away when you try to kill her carry. Or even knock you up and turn you an easy prey for him. Play passively against a lane that has a support.

Jarvan IV can knock you up with a little combo. Well, he will probably use it to open an attack, so you better be ready to counterattack him.

Jax has an annoying stun, but you are not an AD champion, his dodge is useless. If he jumps on you, retaliate. Keep your mind on farming. He is someone you have to beat late game, be prepared.

Karma is an all-in-one support. Heals, shield and speed ups/downs. Cut her heals and attack her when she is out of Mantra.

Karthus will hit you very hard you if you stay at a single place for more than 1 second. It is worth only if you are ulting. Be extremelly careful for his Requiem when going back.

Kassadin Has a short cooldown silence, Null Sphere. Be extremely defensive when fighting him.

Katarina. I'd suggest you to play on a defensive basis, only counterattacking and punishing her if she farms with Shunpo.

Kayle has heals, so, use Preparation along with Bouncing Blades frequently. If she escapes with her Intervention, follow her and Shunpo her to death.

Kennen has a stun, but he need 3 marks of the storm on you to effectively stun you. Dodge his skillshot and trow some Bouncing Blades. It will be a bit hard to kill him since he can speed up, so just harass him from time to time to send him back.

Kog'Maw has two ways to be played, AD or AP. AD Kog'Maw will be like other AD champions, but with a super-high range with Bio-Arcane Barrage. He will give you a hard time farming. On the other hand, AP Kog'Maw relies a lot on Living Artillery to do damage, so you can Shunpo somewhere near to dodge it.

LeBlanc has a LOT of burst damage. Play extremelly passive and try to farm as much as possible without dropping your health too much.

Lee Sin will knock you away with a couple of skills, but he is no great danger to you. If you both have equal farming you should win. Remeber that he is AD, so don't stay near him too much, trwo some knives and then burst him to death.

Leona has some nice CC, try to avoid fighting her 1v1, because she can easily target you with Sunlight.

Lulu has a polymorph and Wild Growth that will cancel your ult. But her polymorph shares cooldown with her speed up/AP buff. When you see she buffed herself/someone else, wait untill it runs off and combo her. Fighting against one will be a headache since she can target someone else to ult and cancel your ultimate, so try not to fight her directly or get her with cooldown on Wild Growth.

Lux has nothing to stop your ultimate. When you see a Lucent Singularity coming up for you, it's time to punish her. Decent Lux player will try to hit Light Binding first, but it's easy to avoid too.

Malphite will show his Unstoppable Force if you ult him or his friends, so take care. Other than that, he has a slow, nothing you have to worry all day all night.

Malzahar is a another guy that is a pain to lane against. His burst may be higher than yours and his ultimate, Nether Grasp will turn you into and easy prey. It will be a hard lane, but at least you can Shunpo somewhere when you see that Call of the Void is comming.

Maokai has a knock back that will give you some trouble, since its on a fair cooldown. Try to hit him with a few Shunpos and Bouncing Bladess until he uses it, then imediatelly combo him.

Master Yi can neglect a few knives from your ultimate with Alpha Strike, but it is no major problem. when he uses Highlander, Shunpo out of that place before he kills you and you will be fine.

Miss Fortune offers a hard laning phase due to [[Double Up] but has no way to effectivelly stop you, other than a meh slow.Farm in the early game, kill her in mid and late game. Dodge her ultimate and you will be fine.

Mordekaiser has a tough shield. Don't be too much aggressive on laning phase, but do some damage when his shield wears off. When Siphon of Destruction is on cooldown, you are free to trow a Bouncing Blades.

Morgana has a snare like Lux, so stay behind creeps and, if needed, Shunpo away from the snare. When she uses Soul Shackles, Shunpo to a nearby minion before it is too late.

Nasus is not a great problem for you. Trow Bouncing Bladess all day, if he can land a Siphoning Strike, retaliate with Shunpo or whatever you have left. His slow isnt good enough to stop you, so he is normally not a problem.

Nautilus has a bunch of knockbacks, so you don't really wanna fight him. Not alone. If you need to, remeber to try to dodge his Dredge Line and to use Death Lotus only after he used Depth Charge.

Nidaleewon't offer you many problems before she gets lv6, to dodge her spear you may use Shunpo. After level 6, she can ger in the cougar form, and it has a nice burst, specially if she is AP. Sometimes, a Shunpo will make you dodge hear pounce and her Swipe, but if you think it is too much risk, just don't do it.

Nocturne is a tough enemy, specially if jungling, when he uses Paranoia, Shunpo away as soon as possible. You can choose to eat his fear and ult after it or Shunpo away if he gets you.

Nunu & Willump is a funny opponent, even tough he can't stop your ultimate, you can´t stop his Absolute Zero, If he has his ult off cooldown, using Shunpo on your combo may not be a good idea unless you are sure you will kill him, or even has Exhaust to make his ult weaker.

Olaf has a nice damage, but he needs to be near you. Don't let him. Use Bouncing Blades whenever possible to hurt him and eventually making him recall, or even kill him.

Orianna will attack you with her ball. Shunpo to her when she thinks she can hit you. If she just used Command: Attack and Command: Protect, you start your combo because her ball will be away from her.

Pantheon has Aegis of Zeonia wich will stun you. Don't fight him if you aren't more fed than him. If he is on the same farm level or above as you, he can wait for your ultimate to stun you, than his Heartseeker Strike will hit you hard.

Poppy will burst you if you are near the wall, so you should stay away from it. She usually opens with Heroic Charge, so if she don't hit you in a wall, you can freely combo her. If she activates Diplomatic Immunity on someone else than you, RUN.

Rammus will often gank you from the jungle. His Powerball will be used to open, but his taunt will screw you anyway. Try to Shunpo out of his range if you are not fed. If you think you can take him, prefer to wait untill his shield wears off to attack.

Renekton isn't a champion that you see often. Anyway, he can stun you and deal some good damage.try to skip fighting him directly, use some Bouncing Bladess to harass and burst him down when he just used his stun.

Riven is a tough hero, with a low cooldown stun. But if she has no lifesteal, it will be easier to keep the pressure with Bouncing Bladess. When you think you can kill her, remember to make her waste her stun.

Rumble isn't seen often, but if he makes the mistake of overheating when you have more than half hp, make him pay. He can harass better than you, but you have more sustained damage. Remeber that Shunpo will help you dodge Flamespitter.

Ryze will be a hard match as a mid enemy, but once you have your ultimate you can try to grab a kill. His Rune Prison won't stop your Death Lotus. Don't try to get in range of him to trow a Bouncing Blades, he will make you pay. Pre-6 early game you should play really passively.

Sejuani has a good AoE damage and Glacial Prison will often get her a kill. Play passively and watch for mistakes while harassing.

Shaco is a pain, specially if he's in jungling. Watch out for his ganks and have your jungler to ward his jungle to keep track of him. Your early game should be even more passive, don't ever push your lane before lv11, thats where he knows you are a threat. If he appears behind you, either run imidiatelly ( Shunpo away from him would be nice) or Death Lotus him. Be careful, though, it will probably be a 2v1, so choose wisely according to your mid enemy.

Shen won't die easily. He has a mitigating shield, a taunt and his ult that will teleport him away in last case. Don't chase him alone and be careful when going for a kill on his team mates.

Shyvana is really an overpowered champion, she can chase well, run well, and damage well. Asking for a friend to help you take her down would be a nice idea. If you can't, do your basic combo and pray.

Singed is a hard match, because if you Shunpo him, he will Fling you even further. Don't try to take him down alone. Just don't.

Sion has two ways of be built, AD or AP. If he is AP he has 2 weakness, his mana and his stun, that if often used for damage, along with the shield explosion. You should be able to counterattack an AP Sion just fine, with your basic combo. If he is AD, you need a partner to CC him. Again, don't try to take him alone.

Sivir has a spellshield, you should only attack her when it is on cooldown, and dodge her skillshot, preferably by Shunpoing her face. If she is fed, ask for some help to CC her.

Skarner will drag you to his team if you are doing well. Just stay away from him, or you will die in seconds. If you have an AoE CC in your team, ask him to use it when skarner starts a team fight (by draggin someone into his team), then you Shunpo in and start roflstomping.

Sona won't be found alone, so only go for her with a friend. She is extremelly squishy and, if she can't time Crescendo extremelly well, she won't survive. Remember to cut her heals.

Soraka has a silence that will annoy you as hell. Remember to cut her heals and attack right after the silence. Just like Sona, try to have a friend near, because you won't find her alone often.

Swain: I don't really see this champion often, just keep in mind he has a delayed stun (wich you can dodge with Shunpo) and fight him like most mid casters.

Talon is a beast if played well. you should buy your Chain Vest earlier against this mage slayer if he is more fed than you. Gosh, you may even need your Zhonya's Hourglass earlier. IF you are more fed you can just wait for his silence to wear off and combo him. He will use his ultimate to escape, so remember to always activate your Hextech Gunblade.

Taric is a support champion with a stun and heal. Be careful to not be stunned in a bad situation or his mate will hurt you. Judge well if you can or not kill him and his partner, cause it isnt hard that you end up feeding his carry.

Teemo is another squishy target. All he has against you is movement speed. Make him use his Move Quick before unleashing your full combo.

Tristana is an enemy that will outlane you easily. She can escape your combo pretty well and burst pretty well too. Play defensivelly, because, if needed, she can even cancel your ultimate.

Trundle dont have anything that will stop your ultimate, but he can run extremelly fast. Take care if you are going against him without your ultimate, if you Shunpo to him and he decides to counterattack, he will block your way back and slow you. That will hurt.

Tryndamere can't be allowed to farm in lane. Never. Gank him whenevr you can, specially pre-6. Making him waste his ult is also nice, because he will play defensively until it is back. If he ever gets fed, buy your Thornmail and ask your team to continously CC him.

Twisted Fate has a low cooldown stun, but it shares cooldown with his mana-returning blue card. when he uses it, it is time to attack him. His ultimate will allow him to gank, but when ganking, they don't often expect counterattacks (of course, Shunpo away if you are very low on health).

Twitch is a squishy guy. VERY squishy. I have actually killed some when they tried to attack me, by ulting and Shunpoing to them. I believe decent Twitches won't do this. If possible, an Oracle's Elixir or even a well placed Vision Ward will save your life, or even grant you a kill. You can even buy a Vision Ward and keep it. If he stealths on low hp you can try to find him.

Udyr needs to be in melee range to damage you. Don't let him. You will need superior farm to kill him 1v1, so don't try if you're not. Ask for a gank and zone him if you're laning against him.

Urgot is a skillshot based champion, so dodge his missiles and specially his Noxian Corrosive Charge. If he hits you with it, run away and wait untill it wears off. He can't do much if you are near him, so shot for a kill specially if he just ulted and you aren't very low.

Vayne can knock you back, and it will cancel your ultimate. She can also dash away even if you stun her. Be careful when ganking her to not give her a kill, she is a very good end-game carry.

Veigar is the burst itself, but you have some tricks to fight him. Harass him in early game after he uses Baleful Strike on creeps. If he places his Event Horizon around you, Shunpo away. Only use your ult after he wasted his stun, but be careful cause he may be taking advantage on your channeling to smash your with a Dark Matter followed by his ult. Ganks are specially effective.

Viktor will harass you with Deah Ray, so e sure to don't stop moving. If he ties to stun you away from him, Shunpo to him and unleash your combo.

Vladimir is a guy that has more sustent than you, but less burst. Harass him a bit so he will use Transfusion on you or a minion to heal up. It's time to nuke. You will need nice judge to know when its viable to follow his Sanguine Pool adn when its not.

Volibear isn't anyone to be messed with. Stay away from him and farm. He can pull you back when you ult, so ask for help to go for the kill.

Warwick will bring a friend along with him to kill you while he uses Infinite Duress, a suppression that will make you a vulnerable target for a few seconds. only go for the kill when he doesnt have his ult up, and remember he can steal a nice amount of life from you every few seconds.

Wukong will imediatelly Cyclone you when he realizes you have ulted, so Shunpo in and go back to lure him into wasting his ult. Be careful for his decoy. If your build is nearly complete, an Oracle's Elixir is welcome.

Xerath will nuke you with his amazing range. Stay near him if you have high health so he has to ult you to activate his stun from Mage Chains. Next time when he leaves Locus of Power, follow him and use your basic combo.

Xin Zhao is really annoying. He will use Three Talon Strike to cancel your ultimate. When you try to gank him, wait till he uses it on the ally on the lane, then combo him.

Yorick has a beast early game sustain and will harass you a lot. Play passivelly and farm when possible. when you grab your ultimate, you can try the kill, but dont be too greedy, he can slow you under turret.

Ziggs has a very high early damage and very high mana costs aswell. Dodge his bombs and try to get him OOM. He can also knock you back when you go for the kill.

Zilean has some annoying time-bombs, speed-ups and a full-life guardian angel. Well, your chance to kill him is to get him OOM or harass a lot.


TL;DR
Wait for their CCs to burst them down.
Play passively early game against ranged champions.
USE your Hextech Gunblade.
Don't be greedy, if you Shunpo under a turret and don't kill the enemy, you can't use it to leave.

Yeah, it's done.
I'd like to say that i appreciate any constructive criticism and/or feedback. Receving a downvote without knowing what i could change would be really disgusting. Anything will help, something i missed or i said that is innacurate, really, any help is welcome.