I've had good luck at Saks Off Fifth, Neimans Last Call and Nordstrom Rack.
I don't know what your figure is like, but mine is tough and it's hard for me to find flattering dresses. I've found that the higher end dresses just tend to have nicer cuts & lines and look better. I think if you're 20 years old and size 2, you can get away with stuff like F21 or H&M, but if not (and I'm certainly not!), try brands like Tahari, Diane Von Furstenburg, and Trina Turk.
I don't know what your figure is like, but mine is tough and it's hard for me to find flattering dresses. I've found that the higher end dresses just tend to have nicer cuts & lines and look better. I think if you're 20 years old and size 2, you can get away with stuff like F21 or H&M, but if not (and I'm certainly not!), try brands like Tahari, Diane Von Furstenburg, and Trina Turk.