Hello there, summoner! Welcome to my custom guide on Teemo, the most evil, devlish, annoying yordle ever! Here I've got you an item build, your farming techniques, and everything else needed to play this fantastic little devil. I am not a pro, let me tell you, but I've played a good while and I know a good bit on Teemo, so let's get started up in here!

Any runes with ability power and attack speed will do you good. Armor, magic resist, and health aren't bad choices either. Truthfully, if you just get teemo's key stats: Ability Power, Attack Speed, and Movement Speed, you probably can't go very wrong.

Pros:
+Has huge burst potential
+Autoattacks have massive damage, both initial and over time.
+Moves around the map very quickly with his W
+Can go invisible for a good ambush

Cons:
-Very squishy
-Weak to tanks and some mages
-Easily ganked

Works with most supports and is HUGE in teamfights. He can get the entire other team low enough health to dispatch with great haste. He can make huge minefields of mushrooms in minutes, stop minions, slow champions, and is simply an essential part of any team during a fight.

He can go invisible and ambush enemy champs. When he comes out of stealth, he gets an attack speed bonus, making him one of the best burst killers.
Teemo has his mushrooms at his disposal, which can help a team in any situation. He can keep minions from advancing, slow escaping and aggresive champions, and get enemies low on health, either giving free kills, or making enemies too scared to come near you.
Teemo can also gank well. His W makes it easy to travel the map to anyone that needs help.

As for farming, Teemo's poison can make it a bit difficult to farm. If it gets the minion's health too low, an ally minion can take the killing blow. So, to farm, auto attack each minion once, wait for it to be low health, and take the gold.

Teemo is squishy, so keep a distance from any melee champions and try to keep close to marksmans to count on keeping a distance like Miss Fortune and Varus.

While planting mushrooms with you ultimate ability, keep some in the middle of your lane to take down minions faster when there's a mass of them. Always keep some in all possible bushes to avoid ganks, keep an eye in them, and for easy kills.

When a melee attacker is getting up close and personal, use your Q to blind them for a few seconds and minimize attack damage taken.

If you are far enough away from an enemy, and you are fleeing from them, plant a mushroom or two and go invisible in a bush. If you are fleeing, you were probably in a fight, which means they've sustained some level of damage. The mushrooms will get them way lower on health. If they both run away, let them, if they keep going, and you are behind them, depending on their health, jump them.