7 STEPS FOR SELF-DEFENSE:
0. LIVE AND BE SAFE - this is "step zero" because it's all about your mindset. Your goal in life shouldn't be "to kick ass" or to be the "local badass" or even "to be respected". It should be to live a happy life, to return to your family or significant other in the evening and to stay in good health. Violence can jeopardize those goals so it's best to avoid it.
Thus we come to #1:
1. AVOIDANCE - don't go into dark alleys, seedy bars and places generally known for being dangerous. Simple. You don't want any trouble now, do you?
If avoidance failed and you're in trouble - go to #2:
2. DEESCALATION - in situations of potential conflict stay calm, don't jump to conclusions, don't provoke or aggravate anyone, don't overreact, don't talk back. Apologize if required and leave if possible. Don't stick around out of curiosity either, even if the conflict is unrelated to you - fights tend to spread like fire.
If deescalation failed and someone is in your face - go to #3:
3. GIVE HIM WHAT HE WANTS - if he wants your favorite spot at the bar, let him have it, you can sit elsewhere. If he wants you to apologize, please do, it doesn't cost you a dime. If he wants you to leave, leave. If he wants your wallet, let him have it (especially if he's armed!). Fighting will always cost you more - more trouble, more health, more money (related to the potential loss of health) and more time in jail if you accidentally kill him (which tends to happen way more often than people think).
If you can't give him what he wants and he is only there to fight you - go to step #4:
4. RUN - yes, run the fuck away. Run to your buddies, to your car, to a nearby police station, run to any place where you will be safer than you are now. In most cases the aggressor won't be keen on following you.
If you can't run or have nowhere to run - go to #5:
5. MAKE SOME NOISE - shout for help as loud as you can, you can try shouting "HELP, FIRE" instead of "HELP, POLICE" since people generally react to the 1st and avoid the 2nd. Many assailants are discouraged by the presence of witnesses and will avoid being caught in the act.
If even that failed then go to step #6:
6. STICK TO WHAT YOU KNOW - if you're already fighting don't try anything you've seen but never done. Never did any kicking arts? Don't kick. Never did any grappling arts? Don't grapple. Stick to whatever it is you've learned and trust your reflexes. In a situation of extreme stress your body will naturally fall on what it knows, no sense trying any fancy shit.
If all has failed and you have been beat up or mugged then go to final point #7:
7. LEARN FROM YOUR MISTAKES - where did it all go wrong? How to avoid the same shit in the future? Really think about that and prepare some solutions. Prevent the same situation from happening. Report to the authorities if necessary - that's what they are for.
Source: personal experience and this excellent post:
http://www.wimsblog.com/2013/04/self-defense-tips-for-men/