Fast food, sodas, and sugar all causes damage to the hair so first you should reduce eating stuff that has a lot of salt, and sugar. Also avoid eating so much pasta, white rice, and white bread. And eliminate soft drinks especially diet ones. Get trims to eliminate split ends and try using heating products as little as possible. Take vitamins, drink lots of water and exercise even if its for 15 minutes, and getting the right amount of sleep also counts so your body can grow your hair.