Kick the nuts full force
You won't become good unless you practice. Find a good martial arts school and join it, practice it and learn... it needs to become a way of life. It's not something you learn once and expect it to work for you years later.
Never fight unless you are willing to die for the cause.
Engage with a goal and make that goal be create a path of escape.
Weapons is always a good idea as long as you practice deploying it and your law allows it. Otherwise it's a bad idea.
If you know martial arts apply it, but remember to defend against what would be considered illegal and cheap in sparring.
If you don't practice anything rush the opponent and overwhelm with very aggressive offense. But time it so that it goes more like a speed of the feet jogging, because any faster and you'll burn out too quickly.
Keep your mouth closed and breath at all times.
Avoid clinching if at all possible and this is especially true if you are fighting multiple people.
If you end up falling to the ground make sure you are on top and try to get back up as soon as you are able.
"Don't be there" is the best tip I can offer.
It can be taken literally - meaning, don't show up for a fight, don't be in places where a fight is likely to happen - and it can be understood from a direct technical standpoint: avoid the point of impact. This is where your stances, stepping, distancing, and balance play a direct role in defensive maneuvering. But to do this well will require a good instructor.
Which brings me to the next best tip I can offer: Find a good instructor. Any style, it doesn't matter - just be sure the instructor fully understands what it is you want, and will deliver.
I suggest you check out the Suzy Lamplaugh Trust. They teach self defence, but don't teach any fighting techniques. Their information will help you avoid situations which may turn violent.
Kajukenbo is good.
Yes. Run and run fast. Call 911. Avoid fighting.
This is just a few good ones.
Find a good school that teaches self defense. Then hope that you never have to use what you are learning. Be prepared to use it if you have no other choice.
Tactics or techniques?
For techniques you need a teacher who can make corrections as you are training.
For tactics read 'The Book of Five Rings' by Miyamoto Musashi. There are several translations. Cleary is my least favorite as he ran the writings through his social filter and did not like the Japanese culture. I like the Victor Harris and the Steve Kaufman translations but there are several other translations still.
Train at a martial art or boxing school. Bruce Lee once said, "Knowing is not enough, you must apply." I can tell you the most deadly effective techneques in the world, but you need to practice applying them. A martial art school can also help your reflexes and gives you actual fighting experience.
I'm not really a good fighter, or I'm not sure I've never had to fight someone, but does anyone know some useful tips?
