how do you stop dandruff?

you need to consult a dermatologist. in my case massaging virgin coconut oil and let my scalp absorb the oil for 30 minutes to an hour does the trick, before taking a bath. just do it twice or thrice a month. it's up to you

dandruff is dry skin on the scalp. first you need to wash your hair properly and get it well moisturize, meaning don't keeps it oily because the oil will dry your scalp even more. I haven't tried any of the new things but i remember Neutrogena T-Gel Shampoo. That worked good for me.

dandruff is a fungal infection so you might try a vinegar rinse after you shampoo - if the problem is persistent get a prescription for a topical anti fungal medication/shampoo from your doctor it will be much stronger and much more effective than the over the counter varieties of anti dandruff shampoo

I think the best and most efficient way is wash your hair everyday and keep it clean.Then eat less excitive food and do more physical movement and less mental fatigue.That will help you a lot. If you have try those above but still no obvious effect,then I suggest you go to hospital for some professional advice.