Casting list for best dps, sustained fight:
Make sure VT is always up.
Make sure SWP is always up.
Make sure SDW is on cooldown.
Make sure Mind Blast is on cooldown.
Make sure Starshards in on cooldown (if Night Elf).
Cast Mind Flay while waiting for cooldowns/DoT refreshes. If you have a moment of confusion and don't know what to cast, cast Flay.
For solo'ing, it's much different. I'm to the point where VT->Blast->Flay->Death will kill some mobs before they even reach me. My guess is the best way will be VT->SWP (if mobs live a decent amount of time)->Flay. At that point they should be on or near you, at which point you can wand or Blast/wand. If you find yourself below about 60% on health, throw VE in there as well. Be sure you're facing the other direction and running away while SWP/VE is going off to give you more time and make sure Flay isn't being interrupted. If you need to keep yourself from being interrupted, Rank 1 Psychic Scream is much more mana-efficient than a Shield.