Teemo is going to look to poke the enemy as much as possible in lane as he will usually have the range advantage. Start with defensive items to protect yourself from his early game poke.
When Teemo reaches level 6, do not take any additional paths apart from the pathing that minions take. Teemo’s tend to place Shrooms
on alternative paths around the lane and try to get you to walk into them.
If you are being bullied heavily by the Teemo, get items like Ninja Tabi, Mercury Treads, Spirit Visage as they will reduce his damage output.
Teemo will often place Shrooms
in high traffic areas such as around jungle entrances and in bushes. Do not walk in these areas if you know Teemo has been nearby unless you have a Sweeping Lens.
Teemo may spend most of his mid game split pushing as he doesn’t always have the ability to team fight. Try to use the numbers advantage to help you beat the enemy in a 5v4. Afterwards, you can siege an objective or even take the Baron.
Teemo doesn’t build many if any defensive items. If you spot him, try to take him down at the start of the fight as he will be really squishy and immobile. If you can take him down, the subsequential teamfight should be much easier.
Teemo’s first power spike is when he is level 6. This allows him to trade more effectively as well as plant many Shrooms
around his lane. After he has reached this power spike, do not walk anywhere else in lane apart from along the minions pathing.
At 40% cooldown reduction, Teemo is able to play a lot of Shrooms
around on the map. Try to take unorthodox parthing to prevent walking through them. Additionally, do not walk too close to minions as you will be hit by the Shroom
if they walk into it.
Once Teemo has Morellonomicon. If he has the range advantage, purchase some magic resistance items so you do not get burst down by him when you walk up to farm.