Straight hair: Step 2

Before you even pick up the blow dryer, make sure you apply a heat protective cream to your hair (Prieto suggests using Kerastase Nectar Thermique, $36). This will help protect your hair from breaking into split ends, which can be a major cause of frizz.

Now blow dry your hair in medium sections, using a big brush. "A boar bristle brush is ideal to smooth out the cuticle and prevent frizz," Prieto says. Also, keep the blow dryer pointed downward instead of sweeping it up and down your hair.