NOTE: This guide is probably only good for iron-bronze, but feel free to try it in higher elos and comment about how it went

basically, you sit in lane and farm, poke the enemy laner, don't get ganked, and try not to die. once you hit level 6 you start kicking it into overdrive and you play extremely aggresive. use your shrooms for wave clear so you can easily take first tower and dive as much as possible (as long as you know you can get the kill) If things go your way, you should be fed enough to just snowball completely. However, if you completely inted, play safe at tower and passively farm until you get to the same level as the enemy team. always help your jungler get drakes whenever they first spawn, and if he isn't going for them as they spawn, ping for help on it until he does. remember to poke only as much as possible, it'll not only annoy the enemy laner, but also cause them to retreat more, giving you more time to farm and damage tower. remember, because of teemo's w's passive, recalling is a lot less impactful than dying, so recall as much as you need.