Blow-dryers have become irreplaceable tools. When properly used (and not to excess), they shouldn't cause hair any problems; to prevent damage, use the high-heat setting only when your hair is very wet. And be sure your dryer has enough wattage: Anything under 1,200 watts is probably not powerful enough to dry and style your hair quickly and efficiently.
Before blow-drying, blot your hair with a towel to absorb excess moisture (don't rub). Hold the dryer 8 to 10 inches from your head and use high heat to partially dry your hair (about 60 percent), concentrating on the roots. Be sure to keep the dryer moving at all times so your hair doesn't overheat -- don't aim hot air at a constant position for a prolonged period. Apply gel or mousse at this stage, if you need it. (Use hairspray only after blow-drying so the alcohol doesn't singe your hair.)
With the dryer on medium heat, style your hair with a vent brush until it's about 80 percent dry. For the final drying, use a round, half-round or paddle brush to smooth your hair and minimize frizz. When your hair is completely dry, finish on the cool temperature setting -- cool air helps set the style.
Diffusers are cone-shaped attachments that fit on the barrel of a dryer to diffuse the airflow, or spread it over a larger area. They're great for curly hair because they dry slowly and softly, keeping the curls in place; use low speed and a low temperature. Diffusers can also give volume and lift to straight hair: Flip your hair down by bending over, then direct the dryer to the crown of your head and the nape of your neck.
Finger diffusers, or volumizers, are attachments with long "fingers" that lift and separate hair at the roots, adding fullness without unraveling individual curls. This tool is especially good for long, curly hair that tangles easily.