Well, there's a ton of reasons why your dps might not be all it can be. I'm going to mention the most common, and how to fix.
1. Your spec is sub-optimal. If you speced by picking the shiny talents, this may be the case. Talents are deceiving after all, and the shiny-looking ones may not be the truly shiny ones. If you want to build your own, I'd head here and read. Heck, I'd advocate reading the entire article. It's really useful. I point others to it all the time. For cookie-cutter specs (as of 3.1) try here or here for survival, hit Aspect of the Hare for BM, and here's a slightly out-of-date MM spec 3.08 spec or you can copy mine. Mine does give up some dps for 3/3 Focused Aim and Replenishment though.
If you're up for it, I would suggest reading the EJ threads, but I know that's a lot of theorycrafting and math.
2. Hit Cap. If you are not hit capped, your dps will suffer. To give an example...
a friend of mine has better gear than me. I am hit capped and he is well, at 150 when he needs to be at 260ish. Last raid, I was at 2.7k dps and he was at 1.9k dps. It's amazing how much of a difference being hit capped can make.
3. You're itemizing wrong. Not being hit-capped is simply the most common example of this. Here's what's important and what isn't.
Agility - Gives AP at 1 Agi per AP and crit at 83 Agi per 1% crit. Yay Agility. Your gear should always have some agility on it. If you are rolling on stam/int mail pieces, you're taking shammy gear and they will not be happy. So stop that and go for agility instead.
Stamina - 3 stam=1 ap for survival. Otherwise not important to dps. Nice for raid survival, but your gear will have this as a matter of course. So don't stress it.
Intellect - I love int. That said, mana + regen if you have replenishment or rapid recup + 1AP per 1 int if you have careful aim (which is a really nice talent no matter what your spec). It's nice, but agility is more important.
Hit - Swiped from Less QQ, More pewpew
262.24 Hit Rating - 0/3 Focused Aim
229.46 Hit Rating - 1/3 Focused Aim
196.68 Hit Rating - 2/3 Focused Aim
163.90 Hit Rating - 3/3 Focused Aim
I always take Focused Aim so I can just shoot for 164, but I am giving up some shiny dps talents for it. You have to make your own call on this, but you MUST BE HITCAPPED!
AP- Second only to agility in its awesomeness. You want this. You want lots of this.
Crit, Haste, and ArP - These are nice, but don't shoot for them. Don't worry about them either. Worry about Agility, AP and hit.
Defense, Dodge, Parry, Block Rating, Block Value, Spell Power, MP5, Strength, Spirit, Expertise - NO.
Spell Penetration - No
4. Shot Priorities/Rotations. These are compiled from a lot of reading. If you think I need to alter or if you get higher dps by doing something else, please let me know.
Survival (nontrapdancing)-> Kill Shot, Black Arrow, Explosive Shot, Serpent Sting, Aimed or Multishot, Steady Shot. If Lock and Load procs, shoot Explosive, Aimed/Multi, Explosive
Marksman->Kill Shot, Serpent Sting, Chimera Shot, Arcane Shot, Aimed Shot, Steady Shot.
Beastmaster->Kill Shot, Arcane, Aimed (if you have it), Serpent Sting, Steady
There is some debate about the usefulness of Aimed Shot. I like it, so I use it.
5. Pets. Your pets add to your dps. So, what can you do wrong here? One, bring a tenacity or cunning pet to a raid. You want a ferocity pet, and you want one that's max level. If you don't have one, go pick up a wolf over in the Storm Peaks. Two, make sure your pet is speced for dps. May I suggest looking here for ideas. Those specs are BM ones, but they at least give you an idea of what pet talents are shiny.