Just as curls do, waves can soften angular features, as they do here on Jessica Biel, another classic square face. If you have super straight hair, try spritzing hair with a styling spray, then winding 2-inch sections around the barrel of a curling iron. Finger-comb out and finish with holding spray.
Learn more in "How to Curl Hair" and see more curly hairstyles.
More on face shapes: