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.
Most credits for inspiration for these build go to Blue and his build guide found here: Blue's Exstensive Teemo Guide I've only made slight modifications to suit my own needs and play style. For an amazing guide please see his, this is more for my own eyes but will share for others who may like it.
Get boots first, build Phage go ganking/dragon/towers/farm til you can get a B.F. Sword then build The Black Cleaver. After that finish Frozen Mallet and build the rest as you see fit when possible.
Same as above build boots first, then build Hextec Gunblade and go ganking/dragon/towers/farm for Guinsoo's Rageblade. After that build as you see fit when you can to counter the opposing team.
These builds are mainly for rated battles in 5v5 and are not by any means max DMG max AP builds. They are for maxing survivability while still being able to put out enough damage to gank and be useful in team fights.