THE LOOK Long spiral curls with volume at the roots HOW-TO "Extensions were used to get Jessica's volume, length and curls," says stylist Marco Maranghello of N.Y.C.'s John Barrett salon. "However, a similar effect can be achieved without the extra hair." Blow-dry just-washed hair with a two-inch round brush. When dry, curl small sections of hair using a one-inch curling iron. When the whole head is done, add a bit of shine serum and hairspray for maximum hold. INSIDER TRICK "One-and-a-half-inch rollers at the crown and roots of your hair can be the best way to get Jessica's kind of volume," says Maranghello. BUY ONLINE NOW hairdo Salon Clip-In Hair from Jessica Simpson and Ken Paves, $87.50; hsn.com.