Your spec is not too bad, nor is your glyphing
Your gemming is a bit odd, but not overly bad. You've passed up a lot of spell bonuses I wouldn't have most notably the +9 on the helm. I'd have put a SP/Spi gem there (since you specced 3/3 Student of the Mind), or a nightmare tear. The Nightmare Tear you do have is utterly wasted in the belt socket, it can go in any colour slot and activate the bonus, whereas the belt socket HAS no colour. The Sp/int is a bit confusing, I'd have gone SP and SP/Spi, or at the very worst SP and Sp/Haste
Your gear is not bad, Black Magic is the better enchant for arcane, and you are way over the hit cap, ditch the Hit trinket (go run regular ToC 5 man for Abyssal Rune or Nevermelting ice crystal from H PoS). Haste is as good or better than spellpower for arcane, depending on your gearing.
This just leaves rotation, and we need more information there. Generally it is straight A-Blastx4, A-Missiles if Missile Barrage procced, otherwise keep hitting A-Blast until it does proc. It's the most mindless, hard to screw up DPS rotation I can think of. Pop Icy Veins + Arcane Power for a boost, I usually also add Mirror Image as well just before that. If you have a Bloodlust, don't pop Icy veins but do pop Arcane Power (and then pop Icy Veins + Arcane Power later on, due to the short CD on Arcane Power with talents).
Standard rotation without blowing CDs and trinkets with your setup should yield about 4k DPS, 5k DPS in raids (excluding fun stuff like spellstealing Jaraxus or Valks). CDs should add another 1k ++ DPS.