Instead of white, think seasonal and shop for an ivory or off-white dress. A sash in chocolate brown, plum or navy adds an autumnal accent to your gown. It may be nippy, so stick to heavy fabrics like guipure lace or silk mikado. For a formal celebration, consider a fabric with a shine or luster such as satin or silk velvet. "Traditionally you would not wear an organza or organdy dress," says Mark Ingram, owner of the Mark Ingram Bridal Atelier in New York City. "These fabrics are fine for summer or spring weddings, but they are too sheer for fall." To stay toasty during the ceremony, wear a stole or matching bolero.