Can I have her haircare routine/tips please?

Every time I want to grow long hair I have a problem that occurs (always) with the length my hair becomes less and less healthy. I understood that this is because the vitamins and elements are not enough to the length I have. So I went to the doctor and figured out the problem. I use the haircare products from
this store and also cut my hair pretty often. But still cannot grow it to be long((