Get a Healthy Scalp! "You can’t have full, bouncy hair without a healthy scalp," says Goddard-Clark. To reduce excess oil, dampen a cotton ball with witch hazel, dab it along your hairline and part, and rinse hair with cool water. Fight flakes weekly by adding five drops of tea-tree oil to your favorite shampoo as a booster. Skip conditioner, though, and apply a detangler only to the ends of your hair — your scalp may be sensitive after this treatment.