Focus on the last hits (early game
Ignore enemy heroes unless there is the blatant opportunity for a kill, what you NEED to focus on is getting last hits (hence the quelling blade). If I were you I'd last hit and not join in any fights. If and only if you do get an early kill then a hand of midas is a good option for increasing the farm rate, if you can't get it uber quick then ignore it.
Why the maelstrom
Most people go for a battle fury in this instance because they think it helps them farm and yes in a way it does but honestly, its a waste of an item, maelstrom is a lot cheaper and not only does it give you damage and attack speed but you also get a useful farming mechanism out of the chain lightning, way more bang for your buck than a battle fury. Mask of madness is always a good item choice on void so its safe to pick that up to help set up kills before you get your treads.
Mid to late game
Poor mans is good for a bit of survivability; after this I find rushing a butterfly good because of the insane all round stats and the evasion stack. After this if they have a lot of magic spells go for a bkb, if not then its a choice between a daedalus, mkb or mjollnir in most cases unless they have a hero that requires cleave in which case you need battle fury or mjollnir.