A: The main factors are time and place, though some rules apply universally: White and cream are off-limits, as is anything bright or majorly embellished (it detracts from the bride). You also don't want to clash with—or match—the bridesmaids or the wedding's color scheme. Deep, rich colors and muted metallics are good bets. Because you'll be dancing and getting up and down to greet people, look for resilient fabrics like crepe, lace, organza, or taffeta. Above all, you should feel comfortable. If gowns aren't your thing, you can still be glamorous in a knee-length dress or suit.
Jacket, $195, lace sheath, $645, Love Evening. Taffeta dress, Alex Evenings, $165.