Hairstylist Marco Maranghello, from the John Barrett Salon in N.Y.C., calls this look "friendly and sexy," and therefore perfect for a holiday party. Plus, it's easy to go from day-to-night. In the morning, add volumizing mousse to wet hair and blow it out with a round brush. At the end of the day, flip head over and mist hairspray over it, making sure to get between hairs. Flip head back up and voilainstant volume.