Practice, practice, practice.
The fact that you are willing to go hit the backboard at night is very encouraging.
Of course you need to learn the things Cheetah lists and many more details as you improve. What you need to do is be analytical and critical of yourself as you practice. What is working, what isn't, what new things can I try to see if they work, where's my contact point, when am I getting my racket back, etc.
Every hit should be an attempt at improving, not just grooving bad habits.