I can't fill out the masteries for some reason, but spec into the utility tree. Greed and Pickpocket will help you get the gold you need for the build, also get all four points of Sorcery and both points of Butcher in the offense tree. Go for cooldown reduction and movement speed masteries as much as possible. I don't suggest focusing on the offense tree since most of it is AP based and a lot of the damage in this build comes from mana.