Rankings are based on the following priorities:

1) Curse of Elements if not already on target
2) Shadowburn when target < 20% health and Burning Embers up
3) Chaos Bolt when Burning Embers up
4) Conflagrate
5) Immolate DOT is maintained
6) Incinerate
Grimoire of Sacrifice is maintained rather than summoning a pet

Cooldown Priorities:

1) Dark Soul: Instability
2) Summon Doomguard

Stat Importance

Intellect > 15% Hit > Crit >= Mastery > Haste