If you're blow-drying your hair straight, says stylist Colleen Conway of Visions salon in West Hollywood, CA, use a leave-in conditioner or an antifrizz serum beforehand. Hold your hair smooth with a brush and make sure the air flow from your dryer blows from roots to ends. If you have curly hair and you want to wear it curly, use a leave-in conditioner or a light styling product to hold the curl without making your hair, um, crunchy. Comb your hair through once when it's wet. Then blow-dry using a diffuser attachment or let your hair air-dry. Don't brush or comb your hair again or you'll get the frizzies.