Hi guys,
I've been playing Top-Teemo a lot lately, became very good and now i will tell you how.
Please go for the thumbs-up if you like it. Of course you can downvote this guide too, but please try a few times before you do. This guide will give you detailed information on how to play Top Teemo and win a game for your team. The strategy will be to get massive damage out of Ap-shots. Your E spell does AP dmg on hit and will do some more by poissoning the enemy. With this itemset i recommend, you will get even more AP damage and kill Tanks with Madreds, AD carries by blinding them, AP carries by having too much HP to get killed first and as a plus you will be able to slow them all with Phage/Frozen Mallet and chase them with your W.

How to play teemo:

- Teemo top is the best Pusher in the game. In the masteries you got the extra damage to towers, so use it! but only when you have loads of shrooms in the river and tribush, so you can escape ganks.

- Ward the river before 6 and do not push until you can turtle with shrooms.

- Harass the enemy with your auto attacks (malady stacks + E will do lots of dmg).

- Use the bush to avoid a melee 1on1 in the beginning. (especially if playing against darius. your auto attacks are of lower range than his pull)

- You dont have to always run even if 2on1. Just put a shroom to were you are standing, Q the enemy (if there are 2 blind the one with more dmg), auto attack the weaker one, use ignite and try to make a kill. You can flash away after! this needs a lot of experience and knowledge of other champions, but learning by doing is the best here ! (IT DOESNT ALWAYS WORK) ;)

- Ask for ganks if the enemy has the first kill in Top lane. If you get snowballed, youll lose faster than you think.

Okay, so let's start with the runes. I don't think there is any different way on how to build a teemo runepage, than my version. it's just a perfect mix of Sustainability and damage. You dont need AP as teemo! all your damage comes from auto-attacks! So get your magic pen runes or gtfo ;) Speed Quints might be usefull, but since we are top, enemies will have lots of magic resist, so we need that magic pen.

We dont need AP here neither. Just go for attack speed, magic pen and a little damage to be the perfect farmer. Outfarm them *****es and make me proud!

Again, you don't buy AP stuff. That's ****. We want to win not run around placing shrooms and waiting for someone to stop by. Why do you buy phage before malady? Simple stuff: you dont want to get 1 hited. You are top, not some squishy carry.
Malady, Madreds and Wits end will give you a extremly high AP damage combined with your E. Phage/Frozen mallet is to slow them so you can chase (& ESCAPE!) and Guardians is extremy good in late game. you wont get focused and Q propably will go off cooldown if you fight someone 1on1.

Phage: buy health first!
Madreds: attack speed => damage => madred's razors => finish

Max E for Max damage.
Skill Q once to blind them.
Skill W once to be faster to chase/escape.
Skill R for extra damage when fighting melees and ward the bushes & the river too! Good players wont go into bushes when playing against Teemo!

There are a few things that you should avoid:
Junglers:
Lee (vision).
Rengar (ult detects you even if invisible).
Alistar (Q interrupts your invisibility).

Top:
Irelia (Jumps you like a bouss)
Yorick (harass = too strong)

Others:

Alistar (Jungler / lategame support)
Blitzcrank (if you cant dodge, he can be a hard one. but you got lots of movement speed to do it)
Akali (only lategame, she harmless at top)

Pros:

- Good damage
- Good survivability
- No need to buy wards => more money (after level 6 - BUY THEM UNTIL YOU ARE!)
- Slow + W = perfect chasing
- Doesn't need a lot of ganks by jungler => other lanes can be babysit
- Good farm

Cons:

Can't find any.. only one might be, that it needs some experience to be as Op as others are even if you are newbie ;)

In Teamfights, stay behind. Put shrooms to the ground where the fight takes place to slow enemies and do some extra damage. Focus AD/AP carries and Q them so they are blinded.
You can also go for the tanks cause of madreds/massive attack speed and Magic pen, but AD is more important at first.