Dandruff

Wash your hair up to 2 times a week and let it air dry.

Avoid artificial heat sources (hair dryer, hair straightener, etc).

Protect your hair and scalp from the sun, because it can dry out extra. Always wear something on your head when you go out in the sun or stay in the shade.

Eat fresh and diverse and drink enough. Drinking too little causes dry (scalp) skin.

Avoid scratching if you suffer from itching on the scalp. As tempting as it is, it exacerbates the amount of flakes and itching.