Fire Mage Specs
[1]Classic 10/48/3
[2]Grapes Build for some PVP
If your a deep fire mage your spec should be one of the two above. If not repec your not doing Max DPS!
10/48/3 will give max mana efficiency only use 5/53/3 if PVP some and you your are preparded to use 2 Super mana pots, 2 gems and Evo for every boss fight in Kara (even with 10K mana buffed).
Gear Basics
+Spell Damage is 1st prority. If it has more spell damage then your current gear it is a upgrade.
After that I would work on + Spell to Hit for Kara as mage your gear should be at 4% or higher. 12% is about the gear cap you want you will get 3% to hit from specs above.
You only need 12% + to hit max on boss fights out side of that 4 % is more then enough for all the trash mobs.
Next is Crit (If your not going to raid or do heroics then + Crit jumps + to hit)
After that is INT and Satm.
Penetration is also a key stat I would put it next after Stam. Shoot for a 40 rating.