First of all, if you think that the main thing is power, you need to forget about their view of the fight. Because during a street fight the power plays not the first role. The outcome of the fight is 80% dependent on mental attitude, 15% on the technique (your ability to fight), and only 5% of the power. So the first thing you need to do to protect yourself is to take care of their psychological training, which is largely decisive in this situation.
First things first, forget the rules of fair fight and all sorts of pity for his opponent. You not only will you regret, but at any unexpected moment is ready to strike. If in danger the dignity, health and the more life you or your loved ones, to spare the enemy in such a situation is the exercise of undue weakness. Learn how during battle to turn from a man into a ferocious beast, while keeping the interior cool. Let the enemy not just afraid, but terrified of you.
Pre-arm themselves with brass knuckles or other improvised weapons is fraught with problems with the law, and will you it to yourself to wear always? Better instantly assess the situation and arm themselves with what comes to hand: cudgel tucked a piece of tin or broken bottle. Take it up and go on the enemy. With this handy item as a weapon should not just beat, but to use it as a hand extension. The best defense is a good offense. While you wait in anticipation of the actions of your enemy, he will catch your initiative and moves on you. Your trump card is an instant assessment of the situation, surprise and swiftness.
And, of course, it is impossible not to mention such common emotions like fear. If you have fear, this inner enemy is more dangerous than the one that attacked you and stands before you. Therefore, the first enemy you need to defeat is your own. Stomp your fear in the throat. Imagine that this fight could be the last in your life. Therefore, you need not just to fight, and we will and we must win. And you must have absolute and perfect confidence that you will win.
Therefore, for the determination. Don't think about what you can get from the enemy. The winner is the one who is not afraid to not afraid of pain. Do not spare yourself, and take the initiative into their own hands and strike first.
What if the enemy looks scary, and, for example, above you, two heads and twice as wide in the shoulders? Well, as the saying goes, "a large closet loudly falls." Your opponent is as human as you are, and he has vulnerable places that you simply need to go and make it as painful for him. If you are determined, in your hands, even a nail file or a very ordinary nail, sandwiched between the fingers like brass knuckles can be a weapon. If you still do not feel confident in their abilities, just imagine them naked... and funny. Imagine it in cartoon and comic form. Then you will be easy to regain the confidence that is necessary during battle.
So strength plays virtually no role, and therefore you do not need to have huge muscles. Just need to know the vulnerabilities and get it there. The vulnerabilities of the enemy, the groin (well, it's no need to explain), kidneys, solar plexus, neck, eyes, temples. And if the power to hit the attacker in a place that is located just above the heel, then he can do to become lame in that leg. From this point we can draw two conclusions: 1. knowing the key to neutralize the enemy, can protect themselves even a teenager; 2. their vulnerabilities should be most carefully protected.
Still, the best fight is the bout. Try not to provoke a fight themselves. It is known that most often the fight begins with words that turn into an aggressive altercation. When the limit of patience of any of the parties is exhausted, start a fight. Therefore, the best way to prevent fights in the Bud. Not to succumb to provocations, not to succumb to negative emotions, not to insult and humiliate the enemy. Because aggression breeds aggression.
If you have the opportunity to withdraw from a conflict situation without a fight, use it. Often a fight can be avoided if the unexpectedly to steer the conversation to another topic (on criminal slang - "pull the market"), turning the situation into a joke, to outwit the enemy, to do something unexpected for him or even to "get legs", i.e. simply to run. The situations are different, and we must proceed from the situation itself, but also of the psychology of the enemy. Fighting is a last resort out of the situation and not the best. After all, at stake may be your life or even the lives of your loved ones. But if we fight what cannot be avoided, then you need to attack first and win.
In conclusion, a few words about the technique and force of impact. Although the strength is not crucial, nevertheless it will not hurt to stay in shape, especially because it is good for health. As for equipment, may be sufficient knowledge of several strokes and techniques. But these strokes and techniques must be honed to perfection and their need to constantly or at least from time to time to work out. For this purpose it is possible to enroll in a section of unarmed combat, as well as to train with any of friends or on a makeshift simulators imitating the enemy.