You have a big event scheduled, and you haven’t a thing to wear. Don’t despair! The selection of formal dresses in plus sizes has never been greater with the growing number of specialty retailers that cater to full-figured women. Whether you are in need of a bridesmaid gown, a prom dress, or a full wedding ensemble, you can find a bevy of choices. Before you head to your local mall, though you’ll need a few guidelines for shopping for formal dresses in plus sizes. Many special event…