This build is meant to ramp up hard to lategame. It has insane ambush damage, extremely potent auto attacks, extremely high AP, and extremely high AD.

Your Q is used to do one of two things-
-Save yourself from extremely high amounts of auto attack damage
-Engage in an ambush and render your enemy incapable of responding

Your E is used to do several things-
-Allow you to auto attack your laning opponent from range and get an incredible trade off
-Help you get kills when your opponents think they've gotten away
-Allow you to deal consistent damage while kiting
-Allow you to deal consistent damage during chases

Your W is used primarily for mobility and escapes, although you won't use it unless your're against an extremely mobile, high damage opponent until you level it at 5.

How you survive laning-
-Priority 1: Get poke trades off on your opponents with your autos
-Priority 2: Get good farm because you need a lot of gold for the items that you buy

If you get good poke off on your opponent, go in for the kill- if they die, you have all the more time to stay and farm, and that's how you get fed on teemo. If you die, you also have teleport to get back to lane before they do and get good farm, but it's not optimal.

Your ranged auto dealing linger damage is ideally your #1 way of whittling your opponents down to 0 health. If they decide to retaliate, pop your Q. You also have the option to hide in a bush and Q, auto them to death. It's certainly an option this early but it's ideal mid to late game.

By now, if you're doing well you should have a guinsoo's and maybe start on a lich bane.
Guinsoo's is fantastic because it acts as a finisher after an ambush.
Once you get lich bane, you're going to want to start ambushing your enemy laner and paying attention to their respawn time while farming, in order to just get back into a bush and kill them again. The more xp you get the more AP and AD you'll get, as our runes and natural talent all scale to about 50 AP/AD at level 18.

Lich bane allows you to trigger deathfire touch and greenfather's gift, then get it's own passive triggered and deal extra damage with your autos, finishing them off, ramping up to even more damage with guinsoo's.

Now is probably a good time to buy mobas as well. You might not have your tp up all the time and it's good to be fast out of combat and be able to run into a bush quickly. Your mobas also go well with your W and can help you escape from a gank in half a second if combat wasn't engaged.

At this point it's good to work towards gunblade, and save hurricane and essence reaver for lategame, as they only add insult to injury.

By now you're close to finishing your last item, and you're close to level 18. You're almost complete, and if you played correctly your enemy laner should be shut down, and you should be super fed.

Ambush.
A lot.
Once you're level 18 you can start roaming other lanes, planting vision everywhere with your mushrooms darting around the map with your W and your mobas. Your mushrooms will also have 40% CDR from lich bane and essence reaver, same with your Q. You also shouldn't forget that you have teleport as well, and a well timed TP to another lane can mean the ambush that gets the kill of the game.