Get Essence of Wealth to 1000% then you can focus on other essences.
Don't upgrade Memories before stage 10. By then you should have Wealth at 1000% and focusing on other essences and will passively come by your memories at a higher level, once you get them at higher level you can start upgrading them.
Always upgrade your passive ability at bosses(after wealth).
Upgrade order:
Health
Attack Speed
Attack Damage
Cooldown