If over the counter dandruff shampoos don't work, try stronger ones that use salicyclic acid or tar oil. Make sure you massage your scalp when you shampoo your hair.
Try showering in cool water. Hot showers can dry out the scalp, causing dandruff. Also, try washing your hair less frequently, allowing natural body oils to help moisten the scalp.
Keep hair and scalp clean daily. avoid shampoos that dry the scalp; avoid oils and cremes that are thick and cake on the hair. do not use other peoples combs/brushes. see a dermatologist.
First reduce your stress level. If you don't controll nothing more will be efetive.
Use Head and Soulder's dandruff control shampoo to wash your hair.
Try at least ten days.