I don't even know how this got into detailed explanations of how to gem and reforge your gear.
If you're consistently doing <10k Avg DPS, changing your gems or reforging isn't going to help you because you are either:
1). Too Poorly Geared (Buy a couple cheap BoEs or SOMETHING!)
2). Not playing your class properly (rotation, ability priorities, not using abilities, etc).
In the case of #2, Learn how to play the class.
Sure, there are small bonuses to DPS if you re-arrange gems and reforging, but gemming/reforging is not going make that Arcane Mage who somehow does 5k DPS (I've seen this in H-SFK once) suddenly do 10k+ DPS.
I've taken I-330ish craft alts into holiday battles and did 9-10.5k DPS and they had no gems and no enchants at all. If you're doing <8k, it isn't your gems/enchants/reforging. There's something else wrong.
Edited, Dec 20th 2011 2:09pm by Lyrailis