This is my Teemo guide. Teemo is my main champion, his fun as hell to play, aswell really good. Pretty underrated, he moved down to tier 2 a while ago. But i think he's a tier 1 champion.
He's really good at scouting ( Thanks to his shrooms, also his quick movement speed ).
Aswell as a good poker. I'll demonstrate all the 3 builds you can build Teemo.
First build is

AD teemo, probally the most famous way to build him. He becomes really strong, and camping in bushes will give you a loads of kills! He's great in team fights, and can really destroy that annoying ashe, thanks to his blinding dart! The best way to build Teemo in my opinion.

AP teemo ( Mage ). Full AP teemo isnt that great, it works and all, but you have to rely on your shrooms, also you wont do that much damage in team fights. But you'll get plenty of random kills in the jungle! And that's fun as hell! Use this as a "LOL WTF HAHAHAHA!!111! Teemo build. he worst way to build teemo in my opinion. But really fun to play, so that's a big plus.

AP/AS Teemo. In my opinion, the funniest way to build teemo. His shrooms will deal loads of damage, his Q ( Blinding dart ) will do a crazy amount of damage aswell... And his auto attack, will do a decent amount of damage, thanks to his "E". But you'll need to kite around your opponents. I would say that this is REALLY close to beating the AD teemo. I've played against plenty of AD teemos with this build, and i've been dominating them. But it all depends on your play style. This is the funniest way, but in my opinion , AD teemo is still superior!