Eat plenty of fruits, vegetables, meats, and fish.
Diet may seem unrelated to your hair, but it makes a huge difference. Diet also has the added benefit of improving your body at the same time.
Since hair is made of protein, make sure you're getting plenty of protein in your diet.
Some proteins to consider incorporating into your diets;
lean meats such as chicken and turkey, fish, eggs, soy products, beans, and nuts. These foods will help promote healthy keratin production, which are the building blocks of hair.
Good luck.