Hello, this is my first guide. I can make some mistakes and English isn't my native language so excuse any spelling or grammer mistakes :D

Teemo is an attack damage carry(adc) champion but he is more effective when you build him as an ability power carry (apc). To do that you need a lot of attack speed and ap items.

In this guide I'll give you my core items, that I've tried a lot of times in the league and some items I've never tried with Teemo but I think they may be helpfull for Teemo.

Please read my guide first before you downvote and leave some comments with suggestions. Thank you!

By the way this build is inspired by; Teemo - AP Yordle of DOOM [S3 Updated!]

Pros

• + Excellent escape abilities (mushroom slow, increase speed skills)
• + Blind (shuts down melee)
• + One of the fastest champs in the game (great for ganks or turret saving)
• + Practically free wards
• + Great farming ability

Cons

• - Extremely fragile
• - Always focused
• - Short ranged (compared to other ranged)

Teemo Game Play

My Teemo is an fragile apc Teemo. Don't buy botts and 3 health potions anymore. Sart with Crystalline Flask, Sight Ward and Health Potion. Use the Sight Ward and Move Quick to avoid ganks. Buy Amplifying Tome to start damaging with Toxic Shot and rush Wit's End and Malady before Berserker's Greaves

Teemo's main damage source is Toxic Shot and Noxious Trap. You have to put those mushrooms to the right places at the right time.

Use Blinding Dart to shut down enemy carries in team fights and avoid foccusing, because Teemo is extremley squishy. Tell your team-mates to lure enemy to your mushrooms and kill easily.

At first you may find Teemo a hard to play champion but when you get use to he is one of the most enjoyable champions in the league.

Starting Items

• - Pay once Heal Several Times
• 
• Sight Ward

Core Items

• - Attack Speed, Magic Resist and Basic Attacks Deals 42 Magic Damage
• - AP, Attack Speed and Basic Attack Deals 15(+10% AP) Magic Damage
• - Movement Speed, Attack Speed
• - Health, AP and Slow Effect with Toxic Shot
• - Attack Speed, AP

Last Choise Options

• - For AP, Armor, Unique Active Stasis
• - For Avoiding Foccus
• - For Magic Penetration with Health

camouflage

Camouflage If Teemo stands still and takes no actions for 2 seconds, he becomes stealthed indefinitely. After leaving stealth, Teemo gains the Element of Surprise, increasing his attack speed by 40% for 2 seconds.

This passive makes you a living ward if you stand still for 2 seconds. In the begining of the game purchase Boots and 3x Health Potion, then rush mid lane. Stand still and wait for your enemy. Use your Blinding Dart on him and hit as much as you can. This will give you the chance to farm easily. If your enemy is afk or a new player you can even kill him. (Note: to prevent your auto attacks from hitting anything in range, press 'S' where you want to Stop)

Blinding Dart Obscures an enemy's vision with a powerful venom, dealing damage to the target unit and causing all attacks to miss for the duration. Deals 80/125/170/215/260 (+80% AP) magic damage and causes the target to miss all of their attacks for 1.5/1.75/2/2.25/2.5 seconds.

Use this to shut down enemy adc in team fights. When laning use to keep your enemy away so you can farm easily.

Move Quick Passive: Teemo's Movement Speed is increased by 10%/14%/18%/22%/26% unless he has been damaged by an enemy champion or turret in the last 5 seconds. Active: Teemo sprints, gaining twice his normal bonus for 3 seconds. This bonus is not lost when struck.

This ability gives you amazing speed boost but we'll max it last becasue we took Ghost.
If you don't take Ghost, then max Move Quick second and Blinding Dart last.

Toxic Shot Teemo's basic attacks poison their target, dealing 10/20/30/40/50 (+30% AP) magical damage upon impact and 6/12/18/24/30 (+10% AP) magical damage each second for 4 seconds.

This ability is the main damage source for ap carry teemo. It's DoT effect allows you to run away from a fight and still end up and killing the enemy. It also makes getting last hits easy, so max it first.

Noxsious Trap Passive: Uses a stored mushroom to place a trap that detonates if an enemy steps on it, spreading poison to nearby enemies that slows movement speed by 30/40/50% and deals 200/325/450 (+80% AP) magic damage over 4 seconds. Traps last 10 minutes, Teemo can store a maximum of 3 traps on his at once.

These mushrooms deals 450(+%80 AP) magic damage and slow you enemy. Make sure place them in high traffic areas where minions are not likely to burst them. You should put a point in here whenever it become available.

This, in combination with our Move Quick, will make you so fast that the enemy will be baffled. Can also be utilized to run across the entire map in just a few seconds to score a gank or to save a turret!

If you find yourself being the target of early harass or ganks, take this spell to ensure your survivabiltiy. Also ensure you use it in team fights to provide a heal for your entire team!

Many people like to pick Ignite when they go to the mid lane but I think the Hextech Gunblade's active can do Ignite's job quicker. But it's your choice.

Provides an escape more beneficial than our Move Quick as it allows you to jump over walls and out of slows.

Thanks for reading my Teemo guide, please help me improve by your comments.

Have a nice day...