This guide is about a more aggressive way to play Teemo. He is my favorite champion and I tried many ways to play him. With this guide I had most success, because I like to play Teemo aggressive and not passive like a ward. I hope I can help you with this guide.

Good against:
all AD-carry's, Shaco, Tryndamere, Kha'Zix, and most ap carry's

Bad agaist:
Talon, Morgana, Pantheon, Zed and Tank's in mid game

The Summenor Spell Teleport is very important. With Teleport you are very flexible, because you can easy teleport to your own Mushroom (Noxious Trap), Minions, Turrets and Wards. You must have it.

The Summenor Spell Flash is a commen Spel and every body knows how to use it.

The upgrade "Enchantment: Distortion" gives you 25% cooldown on your Summenor Spells and is a must.

All Items are clever chosen by its function. They are all important together for a successful play. In the next part I will explain the items.
Doran's Blade : good for early lane pressure and good farming
Berserker's Greaves : fast boots with attack-speed for early pressure
Malady : strong in early and late game (because of his two passives)
Enchantment: Distortion : gives you cooldown for Summenor Spells for fast lane changing and ganks
Rabadon's Deathcap : 120 ap + increases ap by 30%, good for toxic shot and passive of malady
Guinsoo's Rageblade : amazing for agressive playing
Liandry's Torment : gives you needed live,magic penalty,ap,its passive countes with ult double
sell Doran's Blade
Blade of the ruined King : perfect against champs with life,attack demage,attack speed,life steal

They mayby look weird, but "pickpocket" gives you 3 gold for hitting another champion with a basic attack (5 sec. cooldown). So it is important to hit other champs. The Masteries also cover your needed mana regeneration. Agood way to save gold in game.

The Runes give you the very important Hybrid penetration, attack speed for the early game and ap for your "E" spell.

I hope I helped you with my Teemo Guide. For questions please give a comment and rate my giude.
Thank You!