How to Knock a Dude Out
Dude?! If you do not know how to throw a punch, don't. If you have read a paragraph on how to throw a punch, don't throw a punch. The first thing you will do is break your hand.
More thoughts and videos below the fold.
The worst thing to do in a serious street fight is throw a punch. Unless you are a highly seasoned fighter, and throw very solid well aimed shots, just don't do it. Your opponent will duck his head, you will break your fist. Lather, rinse, repeat, and you are out of fists to punch with. Bad idea.
The best advice is simply do not go where this stuff happens. But bad people do sometimes come a calling. So, work out, and train with a professional sufficiently so you throughly understand the basics of stand up fighting, and if possible ground fighting.
Caveat: never ground fight if there is more than a single opponent. Ground fighting is about using your arms, legs, and body to control your opponent, and either damage a joint, or choke him out. If there is more than one opponent, you are likely to be beaten senseless before you can accomplish your goals. Don't do it.
The best defenses are:
1. Leave, run, do whatever is necessary to leave the threat behind, and leave the area.
2. Noise. Especially loud noise makers can cause enough distraction to allow you to leave the area before the perps can attack you.
3. If you feel threatened with serious injury or potentially death, use your stand off weapon, pistol. Do not draw it until you are willing to fire the weapon. Do not "flash" the weapon, do not shoot warning shots, simply draw the weapon, and if that does not result in an immediate retreat by the perp, use it. Fire at center mass, and continue firing until the threat stops, then stop firing! If any of this is new, you need to take, or retake a self-protection firearms course. This comment is not a course.
4. If you are without a weapon, and the fight escalates to a physical altercation, there are two primary blows you need to know:
4. (a). Eye gouge. This is only useful if the perp is close. While any impact on the eyes might give you enough room to leave the area, it is best to know exactly what to do. Take a course. Practice, preferably not on your spouse. In a nutshell, my Sifu used to tell me, "Throw your fingers with the intent to sink them in your opponents eyes up to your palm." I think this is good advice. After the eye gouge a quick kick to the groin won't hurt you escape, and evasion plans.
4. (b). The Slap Knockout! One of the best weapons is the open handed slap. Aim for the ear, but target the palm to hit just behind the ear, bring the slap with full force. Small people will simply need to either mate The Slap Knockout with an eye gouge/groin kick or run, either is effective. Larger people who throw The Slap correctly should see the perp knocked out.
None of this is self defense "advice" or training. If you want to be able to defend yourself, you need professional training. Find a good trainer, and train. Eschew fancy Martial Arts Systems which require long dance move like sequences to "belt up." Find a system which allows you to simply train on your core self protection needs. The more you train for anything the better you will be. Train.
The first video shows what an excellent fighter looks like, and how to throw the punch. Unless you have his level of training do something else.
The second video is one of the best tutorials on The Slap Knockout I have ever seen.