Early L->R ( Focus on Gun DMG early then shift to bomb)
Mid Game (Rush Tankbuster and Cooldown then Spirit Burn)
Spirit CountersSkip or Sell Spirit Resilence if you plan on buying this.
Late Game (If Your losing the game focus on Escalating Exposuing for team fights / If You're Winning (hopefully) focus on Pure Damage)
Late Late Game / LuxuryOnly buy when its extreme late game