What to do if i have long hair but not thick. so what can i do to make my hair grow thicker?

Healthy hair: Get adequate sleep,avoid excess sugar & fat, v carbonated drinks, eat enough protein, exercise regularly. Insure you have adequate Iron (like kale & other dark green leafies), Omega 3 fatty acids (like walnuts),vit.E (fruits & veggies), D & B vitamins, biotin & zinc. Avoid sulfates & formaldehyde in shampoos, excessive blow dry heat & curling irons.