Screen shots of all passives and skills are at the below link
For gear you want 150 shadow dagger effect (or 250 is you’ve got some t7s), increased damage per active shadow, increased damage of attacks used by shadows, -3 throwing attack mana cost on both rings, mana efficiency with sync strike on helm, throwing attack damaage
playstyle, for easy mobs just dash through and the 2 shadow cascade will clear. for harder mobs sync strike then dash. if dash is on cooldown sync then manually cascade. for bosses jump on top of them and go crazy. dash provides invulnerability while it’s in use. use it to avoid large damage and reposition.