The secret to cool girl tresses? Hair that looks like everything but looks like you did very little. It’s all about piecey texture, natural-looking waves, like you woke up, tousled it to one side, threw on a sequined slip dress and headed to the Christmas party. Celebrity hairstylist Sam McKnight is the authority on cool-girl hair (he’s worked on Kate Moss, Linda Evangelista and Kendall Jenner after all) and he’s showing us how it’s done. His eponymous line of spray-on hair essentials makes it easy to achieve the coveted effortless look at home. Hit play and master it in time for party season.