Is to not only move quickly, but, knowing your spells well.
For a Mage, it's Greater Malison and Emotion: Hopelessness. Almost any fight is over in seconds.
For a Cleric, it is Greater Command, then, procede to summon or whomple.
I move quickly. I kill everything completely and utterly in my path most times, depending on what I am playing. Solo on the other hand, I don't. But with a party when I need experience, I kill everything. And I do so in the most brutal direct fashion I can muster. I can end most fights in seconds.
My speed solo (Butterfinger's char file reincarneted as a Jester) completed the game in 39 game days.
Speed is fun, but, there is something about slow as well. It all depends on the mood.