I'm going to avoid actual instruction/tips because honestly that type of shit will only help you if you've practiced and used it. Watching UFC and hitting a punching bag goes out the window if you haven't at least sparred a fair amount.
1. Avoid it unless you are confident they are not going to shoot/stab you.
2. Willing to take pain helps alot. Nothing throws someone off more than throwing a sloppy haymaker, hurting their hand, and then their target laughing it off.
3. Be crazy. A few years back guy was starting a fight with me, first shot my nose was literally spurting blood like a fountain. For some reason despite being SOBER I found it hilarious. I was laughing so hard/loud that he and his friend looked like they saw a ghost and ran after he realized I was a bit off in the head.
4. Seriously avoid it you'd be surprised how many people both legally and illegally carry guns/knives on a daily basis and will pull them even when their life isn't in danger.
5. Be on top if it goes to the ground, this isn't UFC where you will get an armbar, even if you could odds are your head will get bashed on the concrete.
6. Elbows/knees, people who don't know how to fight will often be way too close to throw a decent punch. Added bonus of easier to cut someone which is often enough to scare them off.
7. If you lose a fight and only have superficial injuries don't lie about stairs etc, at best you seem like an idiot at worst a coward to talk about it. Be honest but embellish. "Yeah got beat up 3v1 or 2v1 but they ran once I started getting my licks in they ran like they were at a track meet"
Have gotten jumped a few times due to my penchant for being too aggressive/too white/too proud-stubborn while in shitty neighborhoods, and nothing works better than getting a guy down and repeatedly hitting him in the liver. Less evidence for charges + they are curled up in a ball half crying half puking. Not really applicable for someone who doesn't know how to handle themselves.