I see a lot of people loving Teemo, and I see a lot of people playing him. Now before you vote please make sure to test this build out. It provides nearly an equal amount of AD / AP combo'd with a ton of AS. With the proper rune page, masteries, and some practice, Teemo can be a monster. That's right I said it, MONSTER.

Also, please remember this guide is a work in progress.

Update 1: Added 4 new sections. Will be adding images in the near future.

This guide is a work in progress! Any feedback is appreciated in the comments as I continue to update and tune this guide up. This is my first guide, be gentle! :)

Pro's:
Amazing Kiter
Great Baiter
Best Anti-Carry
Strong Harassment in a lane

Con's:
Very Squish
Low HP / Survivability
Focused a lot because he can shut down he enemies team carry.

Summoner Spells
Ignite
Why? It gives you AP, its an anti-heal frenzy, and it does true damage. Awesome for ganks and teamfights all around, strong on Teemo and this build.
Exhaust
Slow, miss, less ap output, chasing [esp with movequick] you can catch up or run away with this 1 spell on Teemo, and its a double blind when needed.
Flash
If you're newer to Teemo, this spell is not a bad choice. If you're wise with it, it's like sex panther "60% of the time, it works every time"

So your team doesn't have many strong champs that can mid? You got it covered.

You don't need to modify your starting items at all either. Grab your boots and your pots and rush mid asap. When you get there - Position yourself just out of the fog of war ahead of where the creep wave will collide and out of turret view and stealth it up.

When you pop out, regardless of who the champion is: Blind & Exhaust & Ignite, if they attack back hit your pot right away you are nearly guaranteed first blood, if not, the enemy champ will be extremely low and you can deny them a ton of money by keeping constant pressure. As soon as you see them coming in for a last hit, get up there with your boots and blow dart (Or Lazer) them.

It's very important to NOT auto attack creeps, this is a huge mistake I see alllllllll the time in nearly every game. Unless you want to get ganked by a jungler or a side lane, do not push back far, you're there to deny and farm at first, not push turrets. However if first blood scores you some time, feel free to push and then B to grab an upgrade, but I prefer to stay in the lane and keep the levels going. I mean, you handled him once, show him you aren't ****ing around ;)

Remember you are the games strongest early game harasser. Even if thats not 100% true, believe it because you can deny a ton of cash and get yourself and your lane partner a few kills with your poison dart and ignite.

Try to maintain control of the bushes in your lane, when you pop out and blind / auto hit a champ and run back in, you will drop minion aggro and get your free hit in scott free.

Be cautious however; you are still squishy - Don't forget it. Your main focus is to last hit, or if you have a carry lane partner with you, to ensure they get lasts hits. Teemo doesn't need huge amounts of gold, you'll get it later don't worry.

Gank time.

Either the enemy team will start to gank, or your team will. Hopefully it's yours and you're doing well.
You should have half of your core now [To be updated]

Start out with your boots, 2x health pots and 1x Mana pot. The mana pot is optional but if you stay in your lane like you should be, you'll need it once you get your shrooms.

Hit your lane as quickly as can and make yourself stealthy in the first or 2nd brush. However depending on your lane partner it may be better to stealth just behind where the creep wave collides.

If you have a stun lane partner you are nearly guaranteed first blood - Stun - Ignite & Blind - Exhaust - Auto - blind . First Blood! Note this isn't always the case, communication is key.

Let your lane partner last hit ! I see a lot of Teemo's rushing to last hit, you shouldn't be. Your items are rather inexpensive and also with wriggles later on will allow you to catch up on cash with ease.
From 1-6 you should be focusing on poking and harassing non stop - this is for 2 reasons:
1. Most champions ults will destroy you if you let them.
2. It allows your lane partner to last hit and denies them a ton of them.

When you have enough cash to hit base grab a vamp scepter / razors. Depending on how hard you're taking a beating or not in your lane.

@6
Shroom time - Hope you brought that mana pot .

Immediately start shrooming not only in optional locations like the sides of walls (because most think to avoid them and hug walls - wrong.) But in optimal chance of hit locations like Y's in between crossroads and in bushes where you could potentially get ganked.

If your lane partner is alright at this time, you should have wriggles and boots. You can either go gank a lane or two, or grab blue and red.

You will be constantly oom ( and should be ) from dropping shrooms. Try to almost never have any shrooms on you unless you are planning on setting up a team fight. Covered in the next chapter.

Teemo as you may or may not know is a very squishy champion.
In a team fight your role is simple, keep the carries shut down and get in and get out.

Let your tank / OT initiate and kite through a few shrooms if you have some set up, throw your blind out and spam the squishiest target on their team.

After blind, exhaust; Or blind 1 carry and exhaust the other. It can 100% turn your fight around if executed correctly. Ignite on anyone with HP regen / Heal [Mundo, Soraka, Janna]

Adding Shortly.

So you've got yourand your x2&you're ready to lane like a boss.

After some farming and what not, follow the build shown above in the guild or cheat sheet.
Keep this in mind however, situational items DO make a difference.

The thing with being a hybrid is that you want to be balanced, this build provides nearly a perfect balance of what you need to DPS. Not burst, DPS. There is a major difference. Hybrids will be negated evenly, and not completely negated by 1 piece of armor because all of your abilities mesh very well together.

If you find yourself in a very late game; here's some issues you'll have with your gear:

1. DPS Drop on tanks;

you should have a carry taking care of that, and you shouldn't be attacking him first with hisyou'll rapidly find yourself near death by doing nothing but attacking.

2. Survivability:

The build shown in this guide is straight up Glass Gannon Teemo. The thing is, you shouldn't be in a position where you will be killed instantly in the middle of a teamfight. You should be back somewhere else in the corner with an escape route ofto cover while you get the hell out of dodge if things go sour, nobody likes to get aced.

3. Being caught before catching;

This build has little room for error, if you are certain your team is doing great and you can roam the jungle and put's everywhere, do so. But if you're on defense - you'll want to shroom safely, inside or in a line by your turrets to prevent dives and insta turret gibs. If you get caught by somebody you can't 1v1 late game in the jugnle, you will be punished. And your team will rage at you for being a noob, nobody likes a noob, especially a Teemo :p

4. Over-****ing-Extending;

This crumbles teams in more matches than I can even think of. You aced the team, but the 1 person that can stomp you all while your low is up by the time you get to their turret. You're super duper excited and you're like googogogogogogoogogoo. Then as they spawn 1 by 1, you all get owned, and they win.
Take what you just got and know when to pill. It matters most late game, and it matters even more that you're ultra-squish of the year. Take what you got, go back and shroom stuff up.

5. Back-dooring;

While this build allows you to zoom across the map pretty quickly and push a tower fast, don't do so unless everyone is accounted for on the map. Because guess where they're headed?
"Teemo is pushing top, free kill go go" you think you turned and ran quick enough, but they went behind the turret like they always do and curb stomped your little yordle head in. You need to know when to stop and when to go.
However Don't forget you have stealth. Your passive will save your sorry little sneaky *** so many times your team will lol for 5 minutes when they chase you and you're sitting right on top of them and there ain't **** they can do about it. If you went to far, step in to the fog of war and do not move. IF nobody was intelligent enough to get an oracle, you'll sit there and be able to pill back very shortly.

Here's a list of champs that Teemo you'll love, and hate.

Foes: These champions can really ruin your day playing on Teemo, you've been warned.
Janna - Shield, speed, knockback heal.
Soraka - Silence, heal, heal, heal.
Jax - Jump, half hp gone, dodge auto attack, stun, dead Teemo
Cho'gath - Om nom nom.
Karthus - he'll **** on your day with his ult, unless Soraka is there to counter him, Pill if you're low.
Kassadin - Silence, bukkake, warp - dead Teemo
LeBlanc - Ridiculous range, hits hard, avoid this chick as much as you can.
Gangplank - Click - Boom - No HP Left, Pill back -_-
Xin Zhao - His 4 skills combined will insta gib you. Stay far, save blind.
Akali - HAEAUGH - Ching ching - HAEAUGH - Chick - You have been Slain. Right combo = Death.
Garen - Don't even bother harassing him, just ignore him totally, don't get killed, he'll fail.
Malzahard - Blarrrrrrrrrrrrrrrrrrrrrrrrrrrrrrgh You have been Slain.
Poppy - If she gets beside you, you are nearly certain to die, don't let this happen, ever.

Friends: Here are some champions you'll love to be in a lane / on a team with.
Cassiopeia - Guess what? Your poisons work with her abilities, 100% win laning with her.
Alistar - **** I went to far, Boom knocked up. Ali will save your *** many times, and while his heal seems small, early it can def. change a 2v2 around.
Rammus - Getting focused? Okay....Taunt, pew pew pew whom you please.
Maokai - Combined with your harassing abilities , he is a great lifesaver for you, and can certainly help you get some kills.
Taric - Heal, Stun, phew safe.
Lux - She's no powerhouse, but her mini shield and snare is all you need sometimes.

Champions Teemo gets to LoL at:
These are champions that you really get to piss off, and they will hate you, and try to chase you around and gank you, and that's Exactly what you want.
Pissing off the enemies carries makes them wreckless and promises your team to get an easy gank when they're like "GET TEEMO SERIOUSLY RAGEEEEEEEEEEEE".

TF - You're low, hiding in the shrub. He ults, you drop your shroom in shrub, take a step or two back ; the second he lands, you blind him, shroom pops, drop another, keep auto attacking, and he's dead. [ Of course unless he is crazy fed, which shouldn't happen too often ;) ]

Miss Fortune - Euahahahahahahahahhahah, so you move 2 feet, blind her and auto-attack and she dies. Don't forget to drop a shroom under her feet, it makes the world of a difference.

Master YI - This speedy try hard is always trying to gank, backdoor, and so on. Well the second he comes in the team fight, blind him and watch him die. He'll stack lifesteal, well... you can't lifesteal much when you're blinded o.O

Malphite - He's got his sheild of rocks on him, he is super tough, until you hit him with a blind and auto shot and it breaks and he is like "omg I am so squishy" you can own this piece of rock early with ease.

Twitch - Oh that sneaky monster that has been known to devastate teams. If you're playing against one, get an oracle, blind him and focus him. It makes the enemy team 100% less awesome.