Go here for the GS guide Chuckslol mentioned.
I won't say mine is correct, but the following opener works consistently for me:
- Wait until about 2 seconds until pull (because of my haste)
- pre-use Potion (Potion of Prolonged Power, I'm not rich)
- pre-cast Icy Veins
- pre-cast Ebonbolt
- (Lust if using on pull)
- Flurry (BF proc) (pull timer hits 0)
- Ice Lance
- Frozen Orb (hold for a second if boss will move)
- If FoF procs: Ice Lance
- If no FoF: Frost Bolt
- If BF proc with >3 icicles: FB > Flurry > IL
- If BF proc with 3+ icicles: save for GS
- GS when available, combo with Flurry and IL if I can
After that, the rotation proceeds as normal, and I likely only have a few seconds of Icy Veins left. I normally get so many procs from Frozen Orb that I only get 1 GS in with the damage increase. I haven't simmed if its better to hold FO until after IV runs out so I can try to get 2 GS's into the major cooldown.