1. The bigger they are, the slower they are. A pretty good rule this is especially true if running away from the fight. Also, you can elude some of your burlier assailants by running diagonally. If you are faced with the opportunity to fight or flee, flee is the better option. Even the Karate Kid got hurt in the course of his domination of the entire Cobra Kai.
2. Speaking of rules, remember, thumbs and eye sockets do not mix. Well they might mix if you can get your hands on the face of your opponent. No matter what their skill level, size or strength an eye gouge is the great equalizer.
3. Strike first, ask questions later. Actually, best not to ask questions at all. This should read Strike first, leave immediately.
4. Foreign objects are acceptable, just understand the minute you grab an object to give yourself an advantage your opponent will likely do the same. If you are 100% sure you can immediately stop or end the fight without allowing objects to escalate the violence of the fight then it is a viable option.
5. Know your reach and adjust your distance before the fight even begins, understand the reach you have with each and and back up or move toward your opponent accordingly. Be subtle and don't make any sudden moves unless you are ready to commit to the fight.
6. Never push someone when you can punch him instead. The #1 goal is to end the fight as soon as possible, the longer the fight lasts the more likely you will be hurt.
7. Never turn your back on your opponent. It gives them incentive to try to sucker punch you.
8. Never try to showoff your martial arts, especially ones that involve fancy kicking, as kicks at the beginning of a fight will invariably miss and your opponent will have an opportunity to rush you or tackle you to the ground.
9. Don't hit someone who is down, unless there is a real reason for doing so. Once the other person is down you first move should be towards the exit.
10. Never fight with a cop or a lawyer. Even if you come out on top in the fight you will always loose in the end.