Top your head with something that gives you a little more ventilation – like a crocheted beanie, instead of a solid felt hat or something tightly woven. The added ventilation should help. Because one of the key causes of dandruff is a warm, moist environment – which can spur the growth of yeast. And a sweaty head under a tight hat is a perfect environment. So let your scalp breathe a bit more with a looser hat, and you’ll have less dandruff.