Dimitrios Kambouris/WireImage; Courtesy of Garnier
Keep Short Hair Tousled
To make a cut like Halle Berry's youthful, add volume at the roots, says Marin. Rub in a body-building mousse to achieve lift rather than teasing tresses, which can cause breakage. Our pick: Garnier XXL Body Thickening mousse ($4; at Walgreens).