BEST CUT
A chin-length bob (à la Cameron Diaz, Alexa Chung, or Kiera Knightley) "is fantastic if you have fine, flat hair," says Matt Fugate, a stylist at Sally Hershberger Downtown in New York City. "It falls into this shape perfectly." Don't let your stylist use a razor; blunt tips look thicker and healthier.
See more: The 6 Most Flattering Haircuts for Round Faces
IN THE SHOWER
Every other day, skip shampoo and just rinse a volumizing conditioner through the ends to hydrate and prevent frizz without weighing hair down. Try John Frieda Luxurious Volume Thickening Conditioner.
See more: The 10 Commandments of Mascara
STYLING 101
Wring out hair with your hands, not a towel, to avoid fluffing up the cuticle. Then mist it with a light thickening spray (like L'Oréal Paris EverStyle Volume Root Lifting Spray), which makes it easy to target roots on thin, lank hair. If you have lots of hair, rake through a handful of soft-hold mousse; it holds up to humidity better than other styling products. We like Pantene Pro-V Volume Mousse. To blow it dry, first flip your head over and blast roots with medium heat to add lift. Flip back, and create body with a round mixed-bristle brush (like the Spornette Porcupine round brush).
See more from Allure:
The Top 14 New Summer Hair Ideas
The 12 Best Eye Creams
Vote for Allure's Beauty Blogger of the Year
2012 Readers' Choice Awards
