Teemo's power build, my first build / guide hope u enjoy feedback will be appreciated :)

Greater Mark of Insight (x9) - Adds give an extra 8.55 magic penetration giving teemo that extra damage to enemies.
Greater Seal of Clarity (x9) - Adds to give teemo and extra 10.53 mana per second (at level 18) just to secure not runing out of mana when needed.
Greater Glyph of Force (x6) - Gives teemo and extra 18.36 ability power (at level 18).
Greater Glyph of Intellect (x2) - Adds to give teemo an extra 22.50 manna helpfull wenn mana is most needed.
Greater Glyph of Insight (x1) - Gives teemo an extra 0.57 magic penetration.
Greater Quintessence of Swiftness (x3) - Gives teemo and extra 4.5% movment speed helpfull for catching running enemies.

I have choosen the mastries as shown for teemo to give him extra mana, mana regen, ability cooldowns, attack rate, XP gained rate, movement speed and to also buff ure exhaust + ghost spell.

Overall adding all of these togeather give teemo a small addvantage ine the areas most needed for this build.

- Boots of spped are a great first item to give a addvantage over other champs early in the game, this can give early kills or give a better chance of escaping.
- Fiendish Codex makes a good second item giving teemo 7 mana per 5 sec, +30 ability power and a 10% ability cooldown.

- Nashor's Tooth expanded from Fiendish Codex.

- Berserker's Greaves expanding on boots of speed, giving teemo that extra 25 atack speed and 2 movement speed.

- Rod of Ages is an important item for teemo, it is the only item you will buy that give teemo health, also adds mana + ability power (gain extra mana + ability power ever 1 min untill cap is hit)
- Rabadon's Deathcap is to give teemo a massive power boost to deal alot more damage.

- Void Staff importance is to give extra magic penetration while also giving more ability power, this wll increase damage alot.

- Hextech Gunblade is purchased to make killing minions and buff holders just abit easyer by giving 20%life steal.

- Camouflage can be used well by teemo, you can either use it to jump champs, or to hide, it also gives teemo an 40% atack speed for 3 seconds when Camouflage is broken
- Blinding Dart will be the first ability to use as it gives a time period of being able to deal damage with out recieving any.
- Toxic Shot is a great ability to deal extra damage and also kill enimies that have got away on low health but are still poisned.
- Noxious Trap can be used in many ways, they can be used to get away from champs, to kills mobs of minions, to slow champs, to prevent champs from using cover and to set "mushroom fields" whish can help ure team escape an atack.

Teemo's power, i hope u find this build / guide helpfull and let me know how you get on with this guide, if u have any ideas to make it better or what NEEDS changin or anything at all please let me know will be much apretiated, thank you :)