Katie HolmesTHE LOOK Straight diagonally-parted bob HOW-TO "Ask your hairstylist for a wedgy bob full of texture," says stylist Jerome Lordet of N.Y.C.'s Pierre Michel salon. Get this sleek style by running a flat iron through one-inch sections of hair and finishing with smoothing serum on the ends to keep them smooth. INSIDER TRICK The front pieces should be chin-length and the back should have layers cut into it. "You get the wedge by layering the hair from shorter to longer at the nape of the neck," says Lordet. BUY ONLINE NOW Caviar Polishing Serum, Alterna, $26; beauty.com.