I understand your feeling.
Dandruff us the very common complaints that which patients come up with.
All you need to do is avoid forming if oil on you hair first and then shampoo your hair twice daily with and anti dandruff shampoo. It may be way too power full so kindly dilute the shampoo with water. And so not leave you hair wet after you bath wipe the water dry with a clean and dry towel. Wash your hair when exposed to dirt or pollution. If even after following all these your problem is not improving then you need to consult a dermatologist for your help.