Thick, wavy hair? Great news: Once your strands are good and dirty, you are just a few spritzes away from fall's undone "urban wave" look. Start by misting the entire headroots, shafts, and ends—with a dry shampoo, then coat immediately with a generous layer of hairspray. "That locks the powder onto the strands and gives you this instant, moldable volume," says Jenny Cho. Then twist hair into small sections and walk out the door. Shake out strands to remove any residue when you get to work, scrunch crown, and hello, hottie!