You might want to try taking B-complex vitamins. It's one of the most popular vitamins for skin and hair.
Back in my teenage days (a very long time ago :))
We would stick to the rule of brushing our hair 100 strokes each night before going to bed. We loved having long hair and it always seemed healthy. Just make sure you gently brush from the scalp in every direction. This will stimulate your scalp and bring your natural oils through your hair to make it shiny and healthy.