You know how everyone says you have to see an instructor to learn how to fight, and you can't learn anything off the internet?

This is true, for the most part. There are some things which can be taught verbally/through text with no instruction though.

The first thing you have to take in to account is body language. I won't tell you what, figure it out for yourself. Here's a tip, if you make someone scared, it gives them adrenaline and that fight or flight response. If you make someone feel powerful, they will get cocky and not consider consequences.

If someone is running in to tackle you, to put you on the ground, figure out how to bring your knee up to their face whilst pushing their head down to increase the force. Don't forget body language/facial expressions. That's an easy one though, most people would probably know that. Basic growing up in a city move that one.

If you have a knife and are approaching someone from the front, and they don't know you have a knife, walk towards them smiling, maybe knife right hand concealed blade behind your wrist/forearm. When you get close, cross your legs like a X then back to normal, with fancy footwork. Their eyes should go to your feet. Knife straight to the sternum/diaphragm, slice down, cut it in half. Their ability to hold air in the lungs is gone, they can't scream as their lungs will empty now this muscle has lost control. Exhale as much as you can, and watch how far you can run/chase/adrenal dump before you fall over. Not far, not for long. There are also some major blood supply routes in that part of the body.

If you can get behind them, knife to the brain stem (neck/spine/vertebrae/whatever) and sever/twist. They will drop. All voluntary biology is now gone. Fairly clean, quiet. So I hear.

Improvisation is the key, without it you WILL fail. However, no one would ever do this kind of stuff, it is illegal, and I am not encouraging it. By knowing how to do something hopefully you can figure out a way to counter it and protect yourself from undesirables in society, and then, from there, how to counter a counter. If you learn your own improv, it is harder for an enemy to train to counter it by route learning and they will actually need some of their own intelligence to survive.

What kind of tricks do you know?