THE LOOK Straight With Volume HOW TO Apply mousse to wet hair starting at the roots and working through to the ends. Blow-dry your hair about 60 percent or until the roots are dry. "After lightly combing through the hair and styling into place, the hair will have Jennifer Lopez's playful movement," says Daniel Fortunato of the Patrick Melville Salon and Spa. INSIDER TRICK Make sure to blow-dry the hair before combing through. "Brushing your hair when it's wet will make the hair flat and have less volume," says Fortunato. BUY ONLINE NOW Strong Hold Mousse, Sebastian, $14; beautyofnewyork.com.