if you're straight-lined
Look for: A dress that will create curves where you don’t have them. Try a sheath dress in a wispy charmeuse that’s cut on the bias; the curving side seam will give you a va-va-va-voom silhouette. Or look for a ball gown that cinches in at your natural waist and descends into a full, flowing floor-length skirt: It will capitalize on your slenderness and camouflage a lack of hips.
Keep in mind: If you have a small bust, look for a bodice with some ruching to create volume.