Morbidity - Start every pull with DnD, throw in diseases and spread them with pest, if DDs pull aggro you forgot to switch to frost pres or you choose to ignore the whirling warrior and watch him die.
No Morbidity - every second pull is: Blood Boil, Diseases, Bloodboil, FU-Move, repeat
Frost No DnD - Blood Boil, Diseases, Howling Blast
Frost No DnD but Glyph of HB - Howling Blast, Blood Boil, Blood Boil
Frost Spec + Glyph of Pestilence + Glyph of DnD + Glyph of Howling Blast + Morbidity are your best friends in heroics. If DpS pulls on raid trash then just /violin on their corpse and /dance until they are rezzed (or start yelling at the other tank).