This is a Hybrid Teemo Build, ive played Teemo many times and I found that this is possibly the best Teemo build in the game. This focuses on everything, from attack damage/attack speed/ability power/movement speed/ and lifesteal-spellvamp for suvivability.

Boots of Swiftness - Give great movement spead for the whole game
Nashor's Tooth - great attack speed/good ability power/great cooldown reduction
Trinity Force - great passive's/good stats (ad/as/ap/crit chance/movement speed/health/mana)
Hextech Gunblade - good active/decent ad/good ap/great healing abilities
Rabadon's Deathcap - amazing ability power/great passive
madred's bloodrazer - good (ad/as)/decent armour/great passive for killing tanks

Yes, this build is mostly ap but allways remember that Teemo's Toxic Shot allows his bassic attack to deal magic damage. This also allows him to do tones of damage with his abilities. Building Teemo AD will make his Toxic Shot allmost useless late game. Teemo can still be effective built as an adc but it won't be as effective built as a hybrid.

This build is great for solo top. Allways remember the Teemo poke, just use you're Blinding Dart along with a basic attack then walk away (If playing against an enemy like Xin Zhao, you may want to do this from the bushes). You allways want to place your Noxious Trap in the river and in bushes whenever possible. This can be use to back door verry well late game, use your Noxious Trap as a sight ward to know when you're about to get ganked. Remember to use your Noxious Trap late game for places like Baron nashor and the Dragon.

Once you reach level 5, Toxic Shot will give you a much beter chance in securing the minions without last hitting them.

In teamfights, make sure to stay at te back and use Blinding Dart on the strongest enemy ADC and place Noxious Trap's for massive splash damage. (Pick off the squishies first)

Noxious Trap's do not stack. If you place a Noxious Trap on top of another, the damage will not stack, if you hit one Noxious Trap however then hit another 1 second later the slow time will reset but will not add damage until the posion is removed from the target. (Seperate the Noxious Trap's so you don't waste them)

http://lolcounter.com/search.php?search=teemo

This is a usefull website to view who Teemo counter's and who counters Teemo

Here are some items that counter Teemo:
oracle's elexir
Hexdrinker
Banshee's Veil
Thornmail
Mercury's Treads
Frozen Heart
Vision Ward

I will ad other chapters of whom counters Teemo for the people who are lazy to check :P

Yorick
Rumble
Akali
Vladimir
Fizz
Pantheon
Ahri
Gangplank
Mordekaiser

Olaf
Darius
Garen
Singed
Nasus
Tryndamere
Riven
Jayce