First fight is not letting your guard down and don’t let yourself be surprised. It’s the same thing you do while driving your car, just being on foot.
If you get surprised try to avoid confrontation. Any confrontation is a game of chance, being trained makes you have a higher chance but it never means you can’t loose. If it is a social fight, swallow your pride and give in. If it is about resources, give them your phone or yout wallet. The money you’ll pay in court will be more than is in your wallet.
Second fight: confrontation itself. You cannot avoid or give in, you have to defend yourself.
I trained kickboxing for 2 years, I liked the movement and footwork. I don’t like hitting a skull with a bare fist, too much chance of breaking the hand or having a wound by your opponents teeth (these can cause dangerous infections). Use soft part of the hand against hard target, use hard part against soft targets. I don’t like high kicks, kicks no higher than the knee. if you kick higher a opponent can take advantage of that and work you to the ground. Don’t ever kick towards a knife.
Krav Maga is good but it all depends on the instructor.
Systema is good but I don’t seem to have the body or relaxedness to train it. It might take a while ’till you get it right.
I trained Western Martial Arts for several years. Quite useless in our modern world but I learned footwork, distance and familiarity with handheld weapons. You’d be amazed how much people can disarm an opponent in training and don’t know what to do with the weapon next. If you want to fight an armed opponent, you should know the weapon he holds better than he does.
Don’t train a lot of different techniques. Find out what works easily and naturally for you and excell in that, you should learn a system instead of an art . Train in small groups, one teacher cannot see all mistakes a group makes. If you train a mistake it is hard to train it right again. Be skeptical about what you learn and what you are told. If it doesn’t feel right or is complicated, it probably isn’t and you won’t be able to do it under stress without a lot of training. If a trainer or master can’t stand your questions you should train elsewhere.
Third fight: legal fight. Make sure you know your laws and don’t cross them while defending yourself. It’s of no use defending yourself against a criminal, being fined, imprisoned and having to pay the hospital costs and work costs of the criminal.
Find a lawyer that has defended innocent persons who defended themselves, know what you can do and how far you can, be the first one to call the emergency services, don’t lie to the police but watch out what you say.