Check the vendor in town every 1-2 lvls for flat damage gloves, every flat for the build is massive for dps.
You always want the highest physical damage bow you can find, nothing else really matters on the bow because you don't scale elemental damage.
Artillery Bow at lvl 46 is a big power increase if you get one with %phys (pretty common to find from a vendor or gamble).
Zealot Bow at lvl 39 is another solid base and
Cultist Bow is pretty decent after the buff.
Movement speed on boots is also extremely good if you can find them, try to search the vendor every 1-2 lvls. I would never swap out movement speed boots, only replace them with other boots that have movement speed.
Besides that you're just looking for life/resist on gear, but flat damage is the most important on gloves/rings.
!!!!Important!!!!!
Always salvage weapons with quality for whetstones and always salvage items with sockets for artificers orb, this is extremely important for gear upgrades throughout the campaign.
I also personally prefer to vendor all rares for gold to gamble in act 2 and act 3 for better gear.