Whether you're having a wank yourself, or wanking someone else, there's more to it than just grabbing hold of a cock and pulling. There are no records of anyone catching HIV from wanking, so experimenting with a few of the techniques below is pretty much risk-free. Just don't overdo it and pull too hard or for too long, or you could end up irritating your cock and getting a case of NSU.
In this common technique, you simply wrap your fingers around the shaft of your dick and rub up and down. It provides lots of contact between hand and dick – and more contact means more pleasure. This technique is especially good if you have a big dick; if your dick isn't much longer than your fist is wide you won't be able to stroke it very far, so another grip may be more effective.
The five finger
In this technique, your hand and arm form an angle with your penis, with four fingers on top of the shaft at a diagonal and your thumb below. This allows you to get more control over hand to dick contact, and lets you move your hand along the entire length of your dick, even if it isn't very large.
The three finger
This one is good if you have a smaller penis. Simply hold your dick like you would a pen or pencil. This grip allows maximum control and maximum distance of motion (from the base all the way to the head), but the hand to dick contact is less than with other grips.
This one is kind of a backwards version of 'the fist'. This time grab your dick from the left side rather than the right (if you are right handed). To do this, rotate your wrist so your thumb is pointing down; you may have to pull your dick to the side a bit. It's a little awkward at first, but its an excellent grip to use when you want to try something other than your normal grip for a while.
If you get bored of those, you can find a range of techniques from the belly-smack to the milker at www.jackinworld.com.