Lane Only buy regen/rite as needed, other items are core. If you are getting owned in lane don't buy an orange item besdies H-V Mag, otherwise buy 3 orange items + extra charge asap.
Core This build farms really fast and is great at macro (pushing waves/rotating) try to be efficient with your time and take advantage of your farm speed. Imbue all your items on your snowball
T4 item prio Should always get Reverb every game for your snowball. Only get the others after core is complete, usually I buy Reverb after I get Rapid Recharge and Imp Burst. Reverb>Escalating>Echo>Soul Rebirth
After Lane Suppressor for annoying gun heroes like Haze/Gun - Mystic Vuln if suppressor is not needed, you can also skip some of those and go directly for Alchemical Fire