You want sweatshirts to be baggy, not your face. Stress, lack of sleep, dehydration and poor diet can cause dark bags, says Dr. Ariel Ostad, a New York City dermatologist. So drink water, eat fruits and veggies, and sleep plenty. Meantime, try concealers to cover darkness. For puffiness, place a wet tea bag over your eyes (uh, close ’em first) for 10 minutes. Or try cucumber slices—they contain a puff-fighting enzyme.