What are good tips for growing long healthy hair, at its highest speed of growth?

im always looking for tips and products to grow my hair i really want long hair. my hair grows at a pretty good rate but after it gets to the center of my chest area it becomes very brittle and dead. i really need advice for products and tips to help growing my hair i already take biotin and a multi vitamin which help a little bit. what are other products. and im hoping to find affordable products like garnier or pantene or suave products in that affordable range. i know there is no special pill or lotion to help grow hair faster but i know that there are tips to growing long healthy hair.