If you are wearing a long dress, try wearing your pinned up: It makes you appear more elegant and shows off your face more.
If you are wearing a short dress, try wearing your hair straight down with a little curl underneath: I don't know, it makes it sexy and stylish to me. Also, if you're one of those girls who is going "too short" with the dress, it will take some of the focus off of the dress and more to your face and hair. =) Just thought I would throw that in here.
If you want something not so normal or formal, wear an updo or retro sleek styles. You could even try "natural" textured hair.
Other style options: