Anyone got any advice on how I can get my mage to stop running out of mana so fast? D:

He's level 50 now, but any time I'm in a dungeon, I go oom at least 5 times, easy. 'Cause I'm an Arcane Mage (main spec, OS is Frost) I use Arcane Blast on Bosses, but just use Arcane Barrage and Arcane Missiles (if it procs) on trash mobs. And I have 3 heirlooms too (head, chest and cloak), but alas, the int from those isn't enough.

Anyone have any tips?

(never had this problem with my 85 Balance Druid, ever)