Realistic fight scenes

Hi,
So I'm currently going back over this story I wrote a while back to improve it but I am really stuck when it comes to fight scenes. I am not very knowledgeable when it comes to how people actually move when they fight, nor how their bodies would react to certain injuries.

For example in one of the scenes I am writing, the main character goes to throw a strong punch but ends up punching the wall instead. At the moment, the fight sequence itself and the injury that I described is in no way realistic at all.

I could really do with some help. If anyone knows anything or knows where I should look for some info, I would be really grateful!
Thank you! x

Let's see, upper cut- Usually hits stomach, groin, or face (typically underneath chin)

If you were to punch the wall in an uppercut, you would have to have the person jump out of the way remarkably fast.

This seems to be pretty straightforward and logical about hand to hand combat.

I disagree with the "don't kick him while he's down" rule, as you're writing a novel, and no one in real life is going to be hurt.

What you need to know about fighting is that there are no rules, and the only thing going through your head is the fight or flight response. I'm more of a flighty person, but the fight urge has struck me several times, and yes, you're going to miss if the other person is running from you, or is faster than you. If one character's got another cornered, but suddenly the cornered one is about to get out of the way, the other character could punch a wall. Make him aim for the stomach. It's soft.