Alright, let me try and clear this up from my own knowledge. First, ill try and offer a more in depth description of the different types of punches (as someone who trains in kick boxing and martial arts)
As a pre note, I would like to say that its a good idea to emote your characters fighting stance. My character for example uses a standard boxing stance when hes fighting, which means feet side on and shoulder width apart, elbows tucked, arms up in front of my face with the left in front of the right and chin tucked in. Now to the punches
Lets talk haymaker shall we?A haymaker is the 'punch of choice' of a person who does not know how to box or fight with their fists. A haymaker is a large, swinging punch with your fist. I suppose it can be compared to a hook, however a hook is much more structured where as a haymaker is basically a big swing, hoping to hit them as hard as you can. While it may be an 'amateur punch' a lot of power can come from this. Because lets face it, when a big guy is trying to smack you as hard as he can with a haymaker (and people often step into their hay maker punches) amateur or not, its gunna hurt. A lot. Ill go in to actually taking the punch a bit later. The thing about a haymaker, is that you can see it coming a mile away. No mater how fast you think your character is, I present you a simple question - What is the fastest way between two points? Why straight of course. A haymaker is NOT a straight punch, it is a swinging punch, making it easy for a prepared and skilled fighter to duck under, jab, dodge, counter, use your imagination! But if it does hit you, itl hit you like a tonne of bricks!
Moving on from the haymaker, we have the jab. The jab, is a punch usually done with the left hand (unless your left handed). A skilled boxer will pivot their foot with the punch and make full use of their reach whilst throwing a jab. But what is a jab? Easy! A straight punch! Its fast, going straight from point a to point b, and still packs a decent punch (hurhurhur cause we're talking about punching :P). Now, something I think people need to realise about the jab is that reach plays an important factor and should not be ignored. The jab is a personal favourite mine, because I have long arms, generally longer than my opponents. The easiest way to understand the reach advantage, is to find a friend with much longer or shorter arms than you. Get the person with longer arms to put their fist gently (not a punch) against your face and hold their arm out straight. Now the person with shorter arms holds THEIR arm out straight, and you will notice they won't be able to reach, will mr long arms can. So if you're character has short arms, don't expect to instantly counter someone who's just thrown a jab at you without moving in first. Kicking is a good way of countering a reach advantage, but thatl have to wait another day
And then we have the thunder to the jabs lightning, its companion. The cross. Generally with the right hand (unless left handed in which case with the left hand) it isn't nearly as quick as the jab, but it definitely packs more of a punch. Coming from the hand further back (when in a standard boxing stance) and the dominant hand, when pivoting your foot and putting your whole body into it, this bad boy is quite the power horse and coincides well with the jab, with jab cross combinations. People (usually non trained/skilled) fighters will sometimes pull their right hand back as if 'coiling' the punch before punching someone. Personally I don't do it since it slows you down and gives the opponent a bigger warning, but it certainly adds a little extra mph
Now, for the most part those are the only two punches most people will used. But if your characters a bit more experienced or wants to spice things up, we have the hook and the uppercut
Now the hook is, in a way, similar to the haymaker in that they both get power by 'arcing' the punch. But the hook is a much more structured punch. The most important part of a hook, is pivoting your whole body in to the punch. Whilst pivoting your body with jabs and crosses certainly add power and in some cases reach, you can more or less get away with not doing it. With a hook however, you can't really get away with not turning your feet. A hook involves bringing your fist around, keeping your whole arm parallel to the ground. If you're unsure, refer to this picture http://www.physical-arts.com/training/techniques/images/an_hook_punch.gif
now, while not the BEST quality, notice the way his feet pivot with the punch and his arm and fist are all in line. Thats a hook for ya. A hook can be done with either the front left hand or the back right hand. As with the jab and cross, the front left hand (unless left handed) is generally faster while the back right hand packs a bigger umph
And finally, we have the uppercut. Now, the uppercut comes in two different flavours if you will. Theres the uppercut to the jaw, and the body shot. Now, any one who knows how to fight will know to keep their chin tucked in, as its the first defence against the jaw uppercut. None the less, an uppercut to the jaw can still happen when your jaw happens to be too far out and your opponent goes in through your guard. Done right, this is a powerful, and often KO punch. Then theres the 'body shot' uppercut. The name says it all really, its a body shot. Very very VERY rarely going to end someone, but itl certainly soften em up, possibly damage some ribs depending on the circumstances
Well, I've just realised how much ive written so me thinks I will take a short break before editing in the information on being punched. I hope this helps!