Rankings are based on the following abilitiy priorities:

1) Frostfire Orb
2) Deep Freeze on Fingers of Frost proc
3) Frostfire Bolt on Brain Freeze proc
4) Ice Lance on Fingers of Frost proc
5) Frostbolt

Also use these as often as possible!:

1) Cold Snap (when Deep Freeze cooldown is > 15 secs)
2) Mirror Image
3) Icy Veins

Water Elemental is up
Molten Armor is active

Stat Importance

Hit (to 17%) > Intellect > Mastery > Haste > Crit

Reforging

1) Reforge your weakest stats until you've reached 17% chance to hit
2) Reforge Haste and Crit to maximize Mastery