I have hair that reaches slightly longer than mid back, but it is layered all around and I have some sideswept bangs so the front is shorter.
I try to avoid ironing it as much as possible and I notice it seems to grow faster than when I used to iron my hair a lot.
I don't really use any products besides shampoo and conditioner. I have keratin treatments in my hair every few months, which is why I don't need to iron it much anymore and it also keeps the hair healthy.
They also say trimming it a lot makes it grow faster. I do notice that my hair seems to grow faster after a trim..though if a few months go by without a trim the growth starts slowing down.
Make sure you get plenty of sleep, drink lots of water and ensure that your diet has plenty of lean protein such as turkey, chicken, beans, yogurt and so forth. You can use volumizers, but the above tips will also help a lot too.
You want to lay off products and heat. Keep your hair healthy and clean; free from those things. Vitamin b with c complex helps in hair growth as well. And to get big hair, teaze the crown of your hair with a comb.
My hair is down to my lower back took me forever but eat any foods that help improve your keratin levels its the chemical compound in your hair the that makes your hair strong and grow. Also don't brush your hair when its wet less damaging specially if you want more volume
try that horse shampoo, mane and tail I think it's called