Post lane Order subject to change, L-R should be fine for the most part. Arcane is broken on ball right now. We buy Warpstone and Return fire as we max out ball. Can buy an armor after Magic Carpet/Spirit lifesteal. Late game we engage mainly with ball. try not to take damage/drop your spirit shields before using ball.
mid game/core if you are pressed for slots, sell extra charge. if you are forced to upgrade, first upgrade to improved burst, then improved reach, then superior duration, then superior cooldown. buy in order.