hawkeye saidownload the addon recount and go shoot at a dummy.
That's a good start, but there's a little more to it than that.
Players usually want to know what sort of DPS you're capable of when fully raid buffed. Target dummy DPS is a bit skewed since it's an ideal fight, however you're typically short on buffs, as well as target debuffs.
My advice would be to head into VoA a few times with all of your buffs and your A game. See what kind of numbers you can put up in there. 25 man Koralan is a perfect fight for a hunter to see what he or she is capable of.
Another good thing to have is a performance plugin for Recount. These things can rate you on how well you're performing based upon gear score. There may be a stand alone mod, but I know GearScore comes with a Recount plugin. This gives you some idea as to whether or not you're being all you can be.
Another thing you can do is import your armory at femaledwarf.com. Enable best raid buffs, adjust your shot priority accordingly, and femaledwarf will punch out a best possible spreadsheet value for your DPS. This value is what you're capapble of, however it may not be indicative of what you actually do in game. Anyway, it'll gve you some idea of where you're at in terms of over/underachieving.
Hope that helps. " />