Try a belted A-line, halter-neck style. "The straps draw the eye upward and a belt highlights a trim waist," Gruss says. At left: Twelfth Street by Cynthia Vincent dress ($350; shopbop.com). Claudia Ciuti "Anisette" sandals ($260; at Claudia Ciuti Boutique, New York City, 212-535-3025).
If you're VERY LEAN
Choose a strapless look. It shows off shoulders--practically everyone's best body part. A fitted waist and ruched bust add curves. At left: Diane von Furstenberg "Shaunthi" dress ($325; at DVF The Shop, New York City, 646-486-4800). Felix Rey clutch ($65; at Henri Bendel, New York City, 800-423-6335). Cousin Claudine at Fragments earrings ($210; fragments.com). Le Silla sandals ($795; at Vera, Bal Harbour, Fla., 305-868-8660).
If you're PREGNANT
Pick a bright color in a style that showcases your shoulders, arms and bust. At left: Cadeau halter dress ($200; cadeau maternity.com). By Lizh silver earrings ($95; bylizh.com). Illuminata hoop earrings (on wrists; $275; fragments.com). Marc Jacobs silver sandal