Use it to rush to your lane at the start of the game and become a living ward, providing sight for your teammates in the bushes, or for a sneak attack. Remember the 40% increase attack speed for 2 seconds! (Note: to prevent your auto attacks from hitting anything in range, press 'S' where you want to Stop.)
Q: Blinding Dart
It extends the range of our harass, does decent damage and blinds - which is great against any melee who chase you or for preventing gold farm in your lane. I find that one point is enough and our other skills are much more important to max first.
W: Move Quick
I place higher priority on this than dart because of the amazing movement speed boost. Plus it's Active will allow you to escape almost any gank.
E: Toxic Shot
First point here and this skill should be maxed first after our mushrooms. The majority of our damage will come from this skill. Remember that the DoT does not stack, but it is refreshed upon auto attack. This skill also let's us run away from a fight and still end up killing the enemy with the DoT. With the recent buff to this skill, attack speed is now even more important. Our on-hit damage with a +30% AP ratio is pretty good, taking chunks of life away like a boss. I like to put our first point here because it makes getting last hits extremely easy.
R: Noxious Trap
Being our ultimate, you should put a point in here whenever it become available. As an AP Teemo, these mushrooms hurt. They hurt a lot. I can't even count how many kills I've received while back at my base - make sure place them in high traffic areas where minions are not likely to burst them. I'll cover placement more in depth in another chapter.