This obviously isn't the most detailed guide. As well, there are some slightly more effective ways to play Teemo. In this set up, you are ANNOYING and uncatchable, that is if you keep an eye on the map, and set shrooms in areas to prewarn you of dangerous situations. YOU ARE FAST, there are very few champs that can even contend with your speed. Utilize it to lane hop and control minions while your team does the grunt work of countering/pushing against the other team.

Skills: Depending on who your going against of course. Generally pick up toxic shot first. that way you spit hurts more for a single shot, and not much time applied. also, do not focus fire minions, light them all up, apply the poison liberally to the "affected minion area" you will clear waves pretty quickly. ~~ next swiftness (key) you utilize teemo's speed in this build, the faster you are, the harder for you to catch, the longer you live. (if your caught by a stun, your done for. unfortunately... but learn to "cheese it" out of bad situations early, you have the speed to get right back in if need be) ~~ Blinding Dart, really only works against AD people. useful yes, VERY once you have your razor. then you can start to easily take down champs, watching their health deplete while they miss you. ~~ Pick up shrooms when ever it come available (duh) ~ they are an ult, but not in a sense if you where to play them with an AP build. their used to help warn you, and to help get away. place them in openings to jungle, and in bushes of the kind, create path ways for you to trace back utilizing the slowing ability with the speed of teemo makes it so you will never be caught.

Early Game: Mid, not mid, be an annoyance, go stealth, pop out when champ gets close light them up once or twice and cheese it. let the poison set, rinse repeat. Get the champ low enough, ignite + poison, hopefully you get away with a kill. Then greet every enemy minion with a nice new dose of poison. Sometimes, it may take until you get your shrooms to fully dwindle down a champs health. the pop one, you pop out of stealth light them up with increased dart speed, blind to save yourself from a few pegs of damage, ignite. kill is yours. ~ you have the pots to keep your health up in VERY early game once you get the scepter, you have your heal spell to cover in nasty situations, but you can generally replenish you health being smart about killing minions.

Later Game: Your speed is increased, intensely! and you have the power of the razor to cut through armor, Got the blood razor to replenish health. You can run in, light up a champ, blind them if it's useful, ignite, and come out with a kill, judging your health if you might be able to pull off the kill without a pick me up from the heal spell, grats if you can. if not pop it, get the kill... CHEESE IT. don't sit around. YOU WILL DIE.

Thoughts on the Heal spell, useful to help you escape as well, you have the speed to get away, but your likely to get pegged a couple time in the process, pop your heal, run to some minions (far away) [assuming you have your life steal] and regain health.

I can not stress proper placement of shrooms enough, they save your life. (get the blune to increase the amount you can drop) openings, and throughout the jungle, they are little friends that report locations of enemies. Run in and out of jungle leading champs into your mines. to get away. Using a shroom to quickly kill a minion wave saves time, and boosts your money. but only drop it in the middle of a massive minion horde, to be most effective. also, use it while getting the blune. it kills off the little pesky fire throwers, blind the big guy, drop him. more mana, fast cool downs are your prize so why not. try to get the blune as much as possible.

If your only being followed by one maybe two champs, and your feeling ballsy you might be able to get away with cutting back lighting them up, blinding champ 2, getting a double kill. Its a challenge though, you are a squish, with no items to increase survivability other than speed, so use your speed to your advantage.

This is a pretty hefty priced build, the thirster's aren't kind on the wallet, if your not getting kills, jungle (which you should be doing to place shrooms) and minion kill.

Speed is your friend. use it. ~ you can be off doing your own thing, and when your team gets ready to fight, you can rush in within moments. then bolt away to clear a lane, rush through the jungle, snag a rune, meet back up with your team. Its like your on drugs, being everywhere at once.