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.
Twitch is best used as a carry. To do this you will need lots of attack speed and crit chance. I start off using vampiric septer to keep myself alive early game. My next item depends on how much gold i can rack up before i have to go back. I usually go for the crossbow and boots. Then the Last Whisper and Ninja Tabi if there are lots of melee, if not i get berserker greaves. Next i go for zeal and phantom dancer.