A little backstory before I get going. My guild has started pushing through Ulduar 10, and this will be our third week. I have OT'd or MT'd most the fights we've done thus far (FL, Razorscale, XT, Kologarn, and Auriaya). Currently we are working on the tier bosses, and cleaning up Iron council and Ignis.
The healers have been able to keep me up rather well, but I still feel like I'm off a bit. This is partially due to the fact that I am in almost all Naxx 10 gear, but I also think I may be making some gemming mistakes. This is where this post comes in. I'm wondering if any of you have any tips or suggestions for me. I appreciate your time, anything helps. Thank you.
I would get rid of the parry gems (never gem parry it's too expensive, dodge is much better value), and the hybrid def/parry, def/dodge avoidance gems and regem for:
Dodge/Stam or Def/Stam if you want more avoidance and/or the socket bonus
Exp/Stam if you are happy with your avoidance, because your expertise is very low. Try to get 26 expertise if you can.
I'd enchant your cloak for +defense too, it's better value than gemming for it, and you can use the sockets for stamina.