Tips for growing hair???

I've wanted to grow my hair out for years but I'm not sure how. My hair does get split ends and usually I get a haircut only cause my mom makes me. Does anyone have tips for growing long healthy hair and if I should cut it or not. I want to grow it to about my lower back if possible. I have brown wavy hair that is around my lower boob area and it's always stayed near they're from how many times I get it cut. Thank you