I want to start off this guide with the pros and cons to weed people out that most likely wont be interested. Here we go!

PROS

1. High damage output.
2. Several ways to escape trouble.
3. Built for mid/late game.
4. Deadly poison.
5. Inexpensive items to start the build.

CONS

1. This is an offensive build so Teemo is squishy.
2. You have no quick way to get to fights across the map so you have to predict, which means map awareness.
3. You have more work cut out for you than any other person on your team as you have to be in team fights and cover the map with your shrooms which can get hairy if your alone.

Strategy

Teemo is a special champion. He does so much more than people realize he can do, he just has to be utilized. I am hoping this build will let you understand Teemo a bit better and help you maximize his damage output.

Magic Damage

Many people do not realize teemo utilizes mostly magic damage. He has 3 abilities that deal magic damage significantly. One of those abilities does damage on each basic attack so when you go Ability power only with Teemo, you are severely limiting your damage. This is why I build AP AND Attack Speed with teemo, to get crazy damage!

Teemo is extremely squishy, meaning he dies very quickly. You must have an escape route at all times when joining in a fight and you should rarely initiate a fight unless you absolutely know for a fact you are going to kill the target. The reason is Teemo is hard to escape with and you have to know what your doing, where your gonna run.

Auto-Attackers = Teemo's Best Friend

Teemo is great at harassing. Champions that rely on using their auto-attack are your easiest targets. You can quickly blind them and they become useless for between 1.5 to 2.5 seconds. You can use this to keep them from farming minions, which they hate, and for escaping hairy situations. Its great if they attack one of your buddies, hit em with blind and they are useless, you and your buddy pwn his face.

Hitting an enemy with your auto-attack is essential with this build. You do a crazy amount of damage with your auto-attack so get those shots in as much as possible. Don't be a hero running into turrets or other enemies but absolutely take advantage of your auto-attack.

If an enemy runs in at you and you think you may have a chance of killing him alone, drop a shroom and bait him into or lead into a shroom you already have on the ground. This slows and does nice burst damage and damage over time. If you could only see their faces.

Slinky Method

Act like a slinky. This means, don't stand in one place during fights. Teemo CANNOT do this. You must move around and be unpredictable. If you get caught up in a stun or slow you are toast. Move in and out of fights quickly. Make runs in to blind someone pounding on your buddy to save him and toss in a couple auto attacks.

Look for people with low health they are your best friends. Mundo thinks hes gonna come in with 1/4 health and get some off your minions right? NAW DAWG blind him and auto attack. LOL bye bye Mundo.

The Key to Teemo

We all know what I'm saying when I say F*&^#$ Teemo. Thats what your enemy is gonna be saying after you kill him, after they hit a shroom, after one of their minions hits a shroom, and after their teammate hits a shroom and they get hit with a slow and DoT. They absolutely hate you! This is the key to Teemo. Everybody hates you and you might as well have on a shirt that says "Shoot me, I'm Easy". I'm absolutely serious. I dare you to find a game where every single enemy forgets about the opposing Teemo. They don't and a lot of times they remember to buy oracle's, and don't forget that!

Be One With The Ninja

NOW on to the fun part. Teemo is a ninja. You have to think of him as a weak, fragile ninja that absolutely relies on his sword to survive. The catch is Teemo has one of the most powerful swords in the game, his Auto Attack! You can whittle down enemies from afar rather quickly if you use the slinky method. In and out over and over, unsuspecting, out of sight. Get last hits in even if the shot doesn't immediately kill them, your DoT will. Pop off a shot and run away, if they don't chase you, go back in and get another shot or two off and keep doing that until you've whittled them down to an easy death.

CamouflageCamouflage

(Innate): If Teemo stands still and takes no action for 2 seconds, he becomes stealthed. Moving or taking actions will break Teemo out of stealth and will boost his attack speed by 40% for 3 seconds.
Camouflage is an awesome passive for Teemo. He just benefits from this so much its incredible. You can stalk your prey under cover and wait for them to get close. And when you pop out of camouflage you get a 40% attack speed boost! So remember to use this and use it often!! Remember Ninja!

Blinding Dart

(Active): Obscures an enemy's vision with a powerful venom, dealing damage to the target unit and causing all attacks to miss for the duration.
Any enemy champion that uses auto-attacks as a staple for their damage is gonna hate you. This causes them to miss all their attacks from 1.5-2.5 seconds, rendering them useless.

Move Quick

Teemo scampers around, passively increasing his movement speed until he is struck by an enemy champion or turret. Teemo can sprint to gain bonus movement speed that isn't stopped by being struck for a short time.
Passive: Teemo's Movement Speed is increased by 10/14/18/22/26% unless he has been damaged by an enemy champion or turret in the last 5 seconds.
Active: Teemo sprints, gaining twice his normal bonus for 3 seconds. This bonus is not lost when struck.
Teemo's movement speed increase. Be careful when relying on this spell because as soon as you get struck by a turret or enemy champion you lose the boost.

Toxic Shot

Each of Teemo's attacks will poison the target, dealing damage on impact and each second after for 4 seconds.
Teemo's basic attacks poison their target, dealing 10/20/30/40/50 (+30% of ability power) magical damage upon impact and 6/12/18/24/30 (+10% of ability power) magical damage each second for 4 seconds.
This is Teemo's bread and butter!! You want this maxed out as fast as possible because each time you hit an enemy with your auto attack it poisons them and does damage on impact. The DoT does not stack but if you get a last hit on them with one of these shots it will do damage to them each second for 4 seconds, giving you a great chance to score a kill.

Noxious Trap

Teemo places an explosive poisonous trap using one of the mushrooms stored in his pack. If an enemy steps on the trap it will release a poisonous cloud, slowing enemies and damaging them over time.
Mushrooms are technically Teemo's Ultimate and I find myself telling people this constantly. They get so raging red faced mad that my mushroom killed them and can't believe they do so much damage but I tell them, its my ult :P So I find the best placement for shrooms all depends on your enemy team. I tend to place them all across the map but I especially target their jungle minions. They never suspect it til its too late and it also shows your jungler what they are killing at the time. PUT SHROOMS AT DRAGON AND BARON! Please do this and help out your team :) If you are intensely farming a lane, make trails of shrooms leading into the jungle so you can either see enemies coming or have an escape route.

Runes

Mark of Magic Penetration x 9

These increase your magic penetration to cut through magic resist on tanks. Its great to have early game as I find a lot of times I am laned against an Alistar or Nasus.


Seal of CD Reduction x 9
These give you cooldown reduction which is essential with teemo. He needs faster cooldowns in order to survive. It also gives you more Noxious Traps to drop around the map which increases your kills and assists.


Glyph of Magic Resist x 9
These give you magic resist. This is essential in case you run into an AP carry that doesn't use basic attacks.


Quintessence of Movement Speed x 3
Essential for survivability. The faster you can get around the map the better.

Spells

Flash
This spell is essential for two reasons: Escaping the clutches of a fed foe or getting a last hit in for a kill on someone running away. Either way, this spell is necessary to your survival with Teemo!


Ignite
This is another essential spell for this build. Not only can it finish someone off it reduces their healing regeneration and effects which many of your targets will have because you should be targeting champions reliant on basic attacks.

Beserker's Greaves

These are definitely my top choice for boots. The attack speed adds to his killing power because of his E dot. Each time you hit an enemy you add a dot that lasts about 3 ticks and the more attack speed you have, the faster you can add that damage.

Malady

Not only is this item great to start with because its cheap, it gives him essential attack speed and ability power early game. His dot's become more potent and it adds a second dot that stacks with your E PLUS reduces their magic resistance each hit stacking up to 4 times. Its like this was made for teemo!.

Nashor's Tooth

Ability Power + Attack Speed + Cooldown Reduction + Mana Regen. I get this item MAINLY for the cdr but all of its properties are essential to Teemo. Again, the faster you shoot your poison darts, the more damage you can output. You will NEED the cdr for his mushrooms.

Liandry's Torment

Not only does this provide health, ability power, and much needed magic penetration, you get an additional bonus: Magic spells burn for an additional 5% of their current health. This means each blinding dart and mushroom deal extra damage so trailing an enemy through a field of mushrooms can be devastating to their health!

Rabadon's Deathcap

Here is your staple item. This gives you a tremendous burst of AP mid game and enhances your shrooms to become deadly. Your DoTs become insane and people begin to really cry and QQ about it.

Defensive Items

Frozen Mallet

Buy this if: 1. You need to kite. 2. You need a big boost of health. This item will slow your target by 30% for 1.5 seconds. Each basic attack will slow them so if you have an enemy giving you a bad time because they can either run away from you or catch up to you faster then get this and kite them around the map til you can take them out.

Athene's Unholy Grail

This is a special case item. If you find yourself getting squished by an AP carry, this is your item. It gives you a boost to ability power and a nice amount of magic resistance. It also comes with more cooldown reduction which can help you drop more mushrooms on the map.

Wit's End

Another situational item. This works great if you are going against a Katarina or Mundo as it gives magic resist stacks. It also adds a third source of damage per hit giving you a much easier time fighting AP tanks.

Zhonya's Hourglass

Another situational item. ONLY get this item if the enemy team has 3 or more ad champions. You can't possibly blind 3 people in a team fight so doing the next best thing by blocking their most powerful attacks for 2 seconds can be a game changer. The ability power is tempting alone but remember your entire core build amps up your ability power as much as you need.

Teemo is an extremely bursty ap damage dealer. But he is also made out of paper, like origami! He is that beautiful death lotus. That poisonous butterfly. That frail ninja. But of all things, he is over powered. I've played countless games with him and came out on top of both teams. But it all lies in your strategy. Sure, you can build him with the best build ever but fail hardcore because you didn't go in with a strategy! So I will help you out a bit...

Starting:

This is his worst stage. Teemo is SUPER squishy, and I mean super. You have to play carefully in this stage because it could set the entire game for you. I like to start out with boots and health pots because you will be using the slinky method to go in and get last hits on minions. You definitely want to play near your turret, meaning let the enemy push a bit toward your tower.

Stay away from the river bushes. The enemy jungler will constantly have his eye on you. If he smells the slightest hint of gank coming from top he will be there and you will be square. Squarely dead! Don't even go to that bush until you are level 6 and can start placing mushrooms around. If you are feeling insecure before level 6, sneak a ward in there and it should last til close to level 6.

Early game:

After level 6 you can start placing mushrooms around in the bushes. You will NEED to do this to stay safe. The vision around mushrooms are now a lot smaller so you will likely need at least 2 mushrooms around the river bush. I also place a mushroom in the tri bush behind your turret for safety reasons and backdoor ganks.

By this time you can start getting a little braver and getting basic attacks on your opponent. Each hit does a small amount of damage, but many of them add up over time. You want to slinky here too but since you have attack speed (malady) you can last hit and hit your opponent as well each time you run in. Once the enemy gets to around 1/4 life you can easily take him out. If you need to, flash in and ignite paired with blind and auto attacks.

Mid Game:

At this time you should have your stinger and maybe even a large rod. You can start moving toward mid dropping mushrooms since your support is on the opposite side of the map and has no wards for you. Keep the jungle monsters shroomed up for your jungler and if you are feeling brave and wanting to help him out, go put a shroom on the enemy red or blue. I've gotten many kills that way, watching the enemy jungler die to poison because he can't handle the damage coming from the jungle camp as well as a mushroom.

Make sure you are helping with ganks now. If you haven't already pushed over the top turret, keep yours shroomed up so the enemy minions can't get close to it.

Late Game:

After getting either Liandry's or the Rabadons, you should be unstoppable. Still take caution because you will always be squishy. But never be afraid to get in sneaky basic attacks. With a full build, you can take out the likes of Xin Zhao, Olaf, Mundo, Shyvana etc. 1vs1. Each hit you dish out will take away a nice slice of HP from your target.

Stay in the back of team fights and if someone attacks you, run away. Use your W wisely because it could mean life or death in any situation.

Mushroom Placement:
Blue = Essential Mushroom Placement Locations
Red = Vision Locations for Map Awareness

Hopefully this will help a few players out there to play Teemo more efficiently and be a better asset to your team. Teemo is my favorite champion and rarely I run across true Teemo fans.

This is how I play Teemo. If you don't like my build or strategy then by all means let me know why! And thanks for checking it out! I also have alternative builds for him but this has the most damage output and is generally best for skilled players. If you are noob to Teemo, play practice games first with this build until you get used to it. He is super squishy so playing around with the defensive items first can help you out tremendously when it comes to playing normal and ranked games.

Thanks for looking!