I suggest wearing a nice cocktail dress. If you have a theme color wear that. If you have a black dress add some color such as hot pink high heels, hot pink belt or sash or hot pink jewelry and a hot pink clutch. Any color will do! I noticed some brides wear short white or ivory cocktail dresses with a flower in their hair, which is very classy. If you wanna go sophisticaated casual I suggest a sparkly blouse and a nice pleated or A-line skirt with pearls or nice beaded necklace, nylons, pretty shoes and a matching purse.