So easy, I am almost afraid to tell you.
When a blade comes at you, just flick it away, as you would flick a fly. Redirect your attacker into the most uncomfortable position possible. Gun pointed at you? Step aside. Move. Watch that black hole in the front of it, and keep it bisected, like a half moon.
Snipers around? You're fucked.
Wrists, elbows, these are all your redirect points. Light slaps. Back of your hand. Fast, less than a second. Once redirected, step in and stomp your attacker so badly that if they live, it is purely by accident.
Never kick above their knees (unless they're down, then, have at it...) and don't make a fist, unless you are hammering something on them. Expend too much energy, and you will tire, and they will win.
Arm around your throat from behind? Turn into them as you would turn to face your lover, and now they are yours. Hug them, and take those fist-hammers and beat their kidneys into bloody mush.
Tear their throat out with your teeth. Try for the larynx, but it is human nature to protect that by dropping the jaw, and shrugging up, so go for the carotid. There's one on either side. The jugular will spray, and blind you, and ruin your footing. Read an anatomy book. Pay attention to the pictures.
There's a blow, I believe it's called the 'Hiraken'...whatever, it simply means clapping your cupped hands hard over the attacker's ears...you can clap, can't you? See how easy this is?
When a hand comes at you, simply make the peace sign, catch the wrist in the V, and raise your arm. Now, pause for a moment, and look at the landscape of targets this fool has presented. Gosh, we have ribs (hard elbow shot) and depending on what side of the body you have exposed, we have liver, and spleen, and if you spun them correctly, you have kidneys, always a show-stopper.
Don't use your knees until they make the 'O' face. That means they have bought a ticket to the 'Land O Pain', and you are the conductor on this train. Heck, the engineer.
A trained fighter can use your raised knee (think about it) against you, so you need to keep your feet on the ground until they close their eyes in agony.
And watch for the fake.
And forget the balls. The most beat to shit guy in the world will come to life when his boys are threatened. Instead, cripple him by kneeing him hard in the outer thigh (while you are locking up his arms with holds) or the inner thigh...smash any of those large muscles...
Ladies, if he drops, run. If you're in a fight with a chick, a good knee to the cunt shuts that shit down most riki tik.
If you can brush your hair, and apply make-up, close-in fighting should just come naturally to you. Imagine you and your opponent are locked into a tube, where neither one of you can extend your arms past your elbows.