Please note: I do not take the idea of physical violence lightly; I see it only as a means of stopping those who would do physical violence against me or those I love. Can't we all just get along? Love thy neighbour. Do unto others as you would have others do unto you. And all that good stuff. I write this node to dispel the myths propogated by the unknowledgeable and the unexperienced.
Your dad may be a black belt in any school of training or not, and you may have been taking self defense classes for three years or not, but the cold, hard truth of the matter is this: you're not ready for your first "real" fight. I've been studying tae kwon do for 10+ years and am a third degree black belt. I say this not to impress you or to impose my methodology on you, but rather to get you thinking: I've been in more fights than many, many people, and I don't win 'em all. I say to you: generally, reading a node like this will help you not one bit during a fight, unless you happen to have an extremely analytic mind/memory and a gross attention to detail. The only sure way to not get your ass kicked is to have a bit of experience — sorry, nerds, but this is true.
Even though I have relatively advanced knowledge of the martial arts, I always have a weapon on my person at all times. For over two years now I have had a large knife by my side at nearly all my waking hours, just in case — you never know when what you'd never expect is going to happen, so I try to be ready (also, a big fuck-off shiny knife can be helpful in other situations, like cutting boxes and whatnot). You may opt to do so yourself, but you should always be educated and prepared to use your weapon should the need arise. Don't think any weapon is easy to pick up and know how to use effectively.
Despite the fact that usually, in a fight, your brain turns off and forgets everything it has ever read (which means this entire node is pointless) and instead lets the body fend for itself with the synapses it has been programmed to execute when things go awry, I will offer some tips in the hope of sparing injuries to the citizens of E2.
Note that, generally, the fight you are or are about to be in is not a fight to the death. Whatever reason your attacker has for attacking you is, usually, not important enough to add a homicide charge on top of it. If your attacker is intending to kill you (which you unfortunately have a very small probabilily of knowing beforehand), you're in more trouble than you can handle — run to the nearest police station and don't stop until you've got some immobile force or officer of the law between you and your attacker. If you anticipate being in such a situation without a method of escape, you may want to look like for a node like How to stop someone from killing you or something.
Assuming you're not in mortal danger, your main priority is to escape without causing any damage to your attacker and without sustaining any damage to yourself, not to look cool to the three hot chicks who may or may not be watching from the opposite side of the street. Your best bet is to remove your body from the area quickly and without repercussions.
Now, if none of this works and it actually does get down to fisticuffs, you're going to want to do your damnedest to dodge every strike thrown at you. This is not easy, and is damn near impossible the first couple times. Now, if you're in a situation where you're going to get hit (i.e.: you're not anticipating having any luck dodging punches), keep the attacks and attacker away from the vulnerable parts of your body: namely, the entire face and ear area, the entire throat and neck, the chest and solar plexxus, the stomach and sides (where most people are ticklish), the entire length of the inner arms to the wrists, the groin and the inner thighs. These happen to be the parts of your body with many nerves and essential blood vessels, so getting hit there could result in your losing the fight and being subjected a serious ass-whooping.
Do not attack first. This is a sure-fire way to piss off your attacker more, and escalate the intensity of ass-whooping in for which you already are. If you cannot escape the situation, do your best to dodge every attack thrown at you by moving out of the range of your opponent (move to the side opposite what you think your attacker's strong hand is if you can; move away from your attacker if you don't have room to move sideways). If you cannot dodge in time or don't see the attacks coming, do your best to absorb the attacks with the non-vulnerable parts of your body, like your outer arms. The first step is to stand facing your opponent diagonally, somewhere between 45° and 90° away from your attacker, with your non-dominant side forward. Keep your front arm bent with your fist near (but not in front of) your face and your elbow down but not touching your side. Your rear arm should be in a similar position, with your fist in front of your chest area. Absorbing a punch in the non-dominant upper arm is much better and less painful than "absorbing" it in the lower jaw or solar plexxus. You can reduce the force of impact by moving with the punch (only slightly, not so much as to throw you off-balance) and by keeping your arm muscles relaxed until just before impact. Breathe out slightly and quickly as you tense your arm, too; among other things, this'll make sure you keep breathing. Do not try to block any punches with your forearm, as this can be quite painful when you don't know what you're doing, and can sometimes break the arm of those with weak bones. Just don't do it.
If this method is working for you (and if you're doing it right, which won't happen your first time, it should), continue with it and your attempts to leave the premises until your attacker realizes that attacking you is a waste of time and moves on. Your attacker may also get the notion thot you're a more experienced fighter than zie is, and leave you alone for the rest of your life. This will happen in a surprisingly large number of situations, as generally those who would be attackers are not looking for a challenging fight but rather an easy way to make a few bucks or somesuch. If this method isn't not working for you, it may be time to start trying to incapacitate your attacker.
The best way to incapacitate any attacker, unless your attacker is Inspector Gadget or has a gun, is to get zer on the ground. One normally effective way to do this is to kick the attacker as hard as you can in the back of the knee closest to you (assuming your attacker is standing sideways and not squarely facing you). If this does not quickly put your attacker on the ground, give zer another strong kick squarely to the nearest part of the torso to you, which should throw zer off-balance enough to put zer on the ground and/or give you time enough to remove yourself from the area. If you're too close to get a powerful pushing kick in, or are not confident in your accuracy (kicking your attacker's arm will not do a damn thing), a firm shove to one or both shoulders or the chest area will probably work too, but this opens your vulnerable areas to the attacker and doesn't leave you with a hand to block/absorb strikes. Remember, the real point is not to kick your attacker's ass, but to get you out of a situation in which you would definitely get your ass kicked.
Getting into a grappling contest with your attacker is a bad situation to be in. In grappling, the larger, stronger person with more knowledige of holds and the body's pressure points nearly always wins, and chances are that's not gonna be you. Therefore, your first bit of advice is to not get in a grappling situation by staying out of your attacker's reach. If you're smaller than your attacker, you may also be quicker than your attacker which is a big plus. If you're bigger than your attacker, you have a longer reach and have a better chance of keeping zer away from your body.
If you do end up grappling, your main priority is to stop grappling and not get injured beforehand or while doing so. This is where knowledge of the body's pressure points comes in: if you find a good one and keep pushing on it, there's a good chance your attacker will let you go or release a hold enough for you to wriggle free. Pressure points hurt.
Good pressure points for grappling:
The inside of the elbow, bicep-side — extend your left arm, slightly bent, in front of you and tense up all the muscles in it. Put that elbow on your right palm and wrap your thumb around your arm, into the inside of the elbow. You will feel a taut band of ligaments (they feel like cords or cables and help hold your arm together); put the tip of the thumb on the side of these ligaments away from your body and push down firmly. There is a good pressure point deep in here and if you wiggle your thumb around a bit you will find a place where pushing on it makes your arm feel kinda achy and sore. That's it.
The neck is full of pressure points: stick your thumb in any area on the front of the throat (except for directly on zer windpipe, which is the big thick tube in the very front) and push hard. Pushing on your attacker's windpipe is indeed effective, but is often too effective: it's quite easy to crush someone's windpipe and possibly kill them with only a little too much pressure. A good place to start is where the throat meets the jaw; this can be extremely painful for some time but will not do any permanent damage. The bottom of the thraot, above where it meets the collarbones, is good if you have strong fingers.
The areas around the collarbones are also sensitive. Applying pressure in the space between the two, in the center of your body, can be quite painful. The soft indentation between the middle of a shoulder and the collarbone in front of it is also good; this is what a lot of parents use to subdue their lovable little monsters (well, my parents did...).
Bending joints in ways they're not meant to go can also be effective, but I will not attempt to teach anyone anything about this in writing because misunderstood knowledge, even in the right hands, can be dangerous. If you're really in a pinch during grappling and are pretty sure your arm is about to be broken by the figure four hold your attacker has put on you, you may consider twisting zer nearest appendage (finger, wrist, elbow) in a direction it was never designed to go. Only do this if you have an excellent sense of your strength, and be careful when doing it, as it can be easy to break a wrist beyond easy repair without too much actual force. Don't say I didn't warn you, and if you can help it, don't try doing it.
Of course, the best way to not get your ass kicked is to not fight, but I think that might be under How to not fight and not get your ass kicked. If you seem to get into fights very often, learning some self defense is a very good idea — my favorites are aikido and tae kwon do, blended together in my own special way (somewhat like hap ki do), but YMMV. If you're interested, do a bit of research with the Internet or a phone book (don't just look under "karate," though) or even some friends.
And do not use this information to harm others unprovoked, or at all if you can help it. If you do, I'll find out where you live and hand out some pain with my bad breath, colorful language, and feather duster.