This writeup is geared towards self-defensive fighting. If you attack someone simply because they're smaller than you, you don't like them, or think it will make you look cool, you are an idiot. I trained long and hard to learn these things exactly because of people like that, and the fact that I WAS training was enough to keep them away. If you use these tips for the wrong reasons, I sincerely hope that your entire life is a giant failure. Chances are it already is.

Ground Fighting

A lot of fights, especially when the combatants end up grappling, end up on the ground. Whoever is on top has an amazing advantage, so it had better be you.

Takedowns
If you begin to grapple during a fight, your main objective should be to put your opponent on the ground as quickly as possible. There are a couple of good ways to accomplish this, and the usage depends on your positioning relative to the opponent.

• Outside-Inside Sweep
  If the opponent has a good fighting stance, i.e. one foot forward, one foot back, you can send them tumbling with a quick sweep to their front foot, accompanied by a shove towards that foot. The idea is to kick their front foot out from under them, and then push them towards the side that isn't supported.
• Outer-Leg Trip
  This is one of the best ways to take someone down. Place your foot behind your opponent in a long, solid stance, and push them backwards so that they trip over your leg. If you follow them down, you're in a perfect position to pin them by landing your knee on their groin, abdomen, or sternum. Or, if you're really awesome, you can land your knee right on their solar plexus, right below their sternum, and knock the wind out of them by making their diaphram spasm. This will essentially end the fight.
• Between-the-legs Trip
  This works well if the opponent is, for some reason, using a bad stance, i.e. feet relatively close together. Place your front leg between their legs, behind the opponent's foot. Now, run forward while shoving them at the shoulders. You should be able to force them back over your leg, and then you can go down with them and pin them.

On the Top
You're at a great advantage if you're on top of your opponent, unless you are significantly lighter than they are. Even then, you can very easily limit their movements so that they can't defend themselves and you can end the fight quickly. A few tips:

• Land with your knee
  Dropping on your opponent with your knee can cause serious damage. Do the math in your spare time: almost your entire weight, dropped about three feet, landing on an area the size of your knee, can hurt your opponent really, really badly, and will probably end the fight.
• Turn them over
  If you can get ahold of their arm on the way down, then you can use it to roll your opponent over on their stomach. I wouldn't recommend control holds like this for people who haven't been formally trained, but it is possible for you to hang on to your opponent's arm and, as they hit, push them over and twist their arm towards the inside of their body. At that point you can sit on top of them and do whatever you please, because they can't even see you.
• Get Away
  The best part about being on top is that you can get away, whenever you want. Land a few mean blows, and by that point your opponent should be stunned enough that you can get up and away before they can even think about counter-attacking. As mentioned earlier, though, if you're at all worried about them continuing their attack, keep capitalizing on your position. That is, beat them till they don't move.

On the Bottom
Once someone is on top of you, your options are very limited. At this point, you have only two objectives: 1) preventing as much damage as possible and 2) getting the hell up.

• Preventing Damage
  Chances are good that at this point you're going to get hurt. Here are some things you can do about it:
  • Dont let them pin your arms
    If your opponent has a hold on you, as soon as you hit the ground pull your arms in to protect your face. Sooner or later your opponent is going to get around to hitting it. The main objective is to keep your arms from being pinned between you and your opponent.
  • Move as much as you can
    If you can wriggle around, bobbing your head and such, you can make your opponent miss what they're trying to hit. A glancing blow to your cheek is much better than a piledriver to your nose.
  • Cushion your head
    A favorite move of an opponent if you're on your stomach is to pull your head back by the hair and smash it into the ground. To prevent any significant damage from this, place your arm undernead your forhead, so that your head hits flesh instead of pavement.
• Getting Up
  Getting up is hard to do when someone is sitting on top of you. Your only real hope is to overpower them. If you're not bigger than them, you have to do something to divert their attention to their own discomfort.
• Pressure Points
  There are some very good places that, when put under pressure, can be very uncomfortable. Unfortunately, when you're being sat upon, not many of them will be accessible. But, luckily, my favorite pressure point of them all still is. It's the inner thigh, right up near the crotch. Grab this area with your thumb and forefinger, while protecting yourself with the other hand, and twisting and wrenching your body to get away. Try it on yourself: just a light pinch hurts quite a bit. A heavy, fighting-for-your-life pinch is near incapacitating. In this context, this technique can even be more effective than hitting the groin.
• Biting and Scratching
  If your arms are free, go for their eyes. Few attackers are willing to fight any more if you damage their eyes. On the same note, any control you exert over a person's face puts them at a disadvantage, so keep your hands in their face at all times. Pinch, hit, poke, scratch, anything you can do to make them think about protecting their face rather than beating yours. This just might give you a chance to push them off of you or wrestle you're way out from under them.
• Admitting Defeat
  If you're pinned, can't move, and can't protect yourself, you've lost the fight. If you think your attacker is going to kill and/or rape you, don't stop screaming. Let everyone within a half mile radius know that somebody's about to kill and/or rape you. If the fight is somewhat less serious, convince them that you're not going to fight anymore. The time to give up is for you to decide, but remember that doing ineffectual things to your opponent will only make them hurt you more.

A Grain of Salt
I studied the martial arts for many years, and it is precisely because of that that I have never been in a fight. Anyone who might've been inclined to beat my scrawny ass up already knew that I was studying karate and had to come to terms with that fact before facing me. Also, I learned to be confident in my own abilities against schoolyard antagonists. These two things, more than anything else, were my best defense, and the only things I've ever needed so far. However, I have never been in a real fight, and as was mentioned before, a lot of this stuff will only cross your mind after the fight unless you've had enough training that it happens automatically. Just keep your head and be confident during a fight, and you should be okay.