There's always the tried-and-true method of f*cking with it.
My first AG turned out very watery and uninteresting. Rather than just let it be (like many of the other posters seem to advocate), I dove in headfirst, and did a supplementary boil. I steeped some nice toasty grains in a couple pints of water for 30 minutes. Then I took the grains out and brought it to a boil. I added hops and 5 oz. of maltodextrin powder, and boiled for 30 mins. Then I added that to the secondary. I got a little bit of fermentation...meaning the steeping grains actually converted a little bit. But overall, it helped alot. Gave it more character, better mouthfeel, more fullness, etc. If you're ultimately unhappy with this beer, I'd try a supplementary boil like that.