Not Updated For Current Season
The masteries shown here are not yet updated for the current season, the guide author needs to set up the new masteries. As such, they will be different than the masteries you see in-game.
Normally you would say; "Why don't you get lifesteal first!" or "Critical is for Noobs!" or even "Attack Speed is the Best!".
Well this is a mix of Damage and Critical.
(Note; I'll continue to update now and than.)
I start off with a Brawler's Gloves for the 10% Critical Chance since it really does deal a lot of damage, I also get 2 Health Potions because I find lifesteal very useless with Teemo since you don't go dps till the end.
I than temperately get a Berserker's Greave for the Attack Speed and Movement and if you have enough quickly get the Zeal for the Critical Chance and Attack Speed.
I than go for the Damage and work on the Infinity Edge, depending on your money, if you have 1,850 than get a BF. Sword. But if you have 975 Gold get the Pickaxe even though some of you might want to save for the BF. Sword.