(I typed all this out a while ago for another list I'm on, so here you go with a few updates and revisions...)
If you are looking for basic leash manners when walking there is an EASY way to do it with a prong. It takes about 15 minutes and your dog will teach itself. You can NOT do this with a choke chain. They are useless as soon as the dog is on the wrong side of you or at the wrong angle. This will also not work with a flat collar, because all you do is jerk the dog's neck which is uncomfortable but not much by way of 'correction'.
I wrote this for heeling on the left, but you can do everything on the right if you choose.
Anyway, about the heel. Put a prong collar on the dog and hold the leash in your left hand with the dog on your left. Do not hold the leash with two hands, left only. The collar should be right up behind their ears, and the leash should be slightly slack. There should be a 'J' between you and the dog - i.e. no pressure on the collar at all. The prong should fit snug on the neck and not spin easily. Use the smallest links that are strong enough for your dog, just add more so that it fits. The prong should be a little difficult to get on, but not dig into the neck.
Now walk straight ahead, do not give the dog a command, do not look at the dog, just walk at a steady pace. Watch the dog out of the corner of your eye. When he gets ahead of you QUICKLY turn around. As you turn, let your left hand/arm trail behind you and then when you are facing the other direction bring your hand forward quickly. Continue to walk at a steady pace. Go at least 30 steps so that the dog is walking in a straight line, then turn again if necessary.
Do not turn and then take three steps and then turn again. You will just frustrate and confuse your dog. You need at least 10 steps to get both of you going in a straight line, then a bunch more to give your dog a chance to think about things.
You dog will yelp and may fight the first time you do this. The second time he may yelp as well. You are not injuring him, you are surprising him. You are teaching him through his own actions that he must walk in a position where he can see you and respond to your movements. After two or three turns he should turn with you with no trouble. He will teach himself that getting ahead of you makes him unable to see you turn, and if he can't see you turn he gets a correction. By not giving him a command he is not obeying or disobeying you - he is responsible for his actions - he also can't decide to disobey you and that is very important as well.
Try this out without him on the leash a few times. The turn must be smooth and controlled for it to work. You need to be confident as well, you are letting your dog know that you are the one in control of the walk and if he doesn't want to pay attention to you then he corrects himself for it. I'm sorry if this is hard to follow, I just do it automatically and it's hard to describe completely. (I did think of making a movie and posting it, but both Ruby and Connor are completely unwilling to misbehave while wearing prong collars!) If you are not getting a short 'pop' on the collar when you turn you need to work on your timing. The correction should be quick and short. If you do a long slow pull you will not 'get the point across'.
This may sound mean, but if your dog doesn't yelp the first couple times you do it you're not doing it right. Because the correction is short and fast and only comes when you turn around it sends a very clear message to the dog 'stay with me or you won't like the consequences'.
By making him responsible for tracking your movements you get a very willing 'heeler'. When he is where he belongs, say 'good dog, heel'. Then start saying the command when he is next to you walking. When you say 'break' allow him to roam to the end of the leash sort of push him away from you to get the point across that it's now ok to be out of his heel position, then say heel (and if necessary, turn) to get him back where he belongs.
With the dogs I train there are no 'stay' commands, there is only a command that the dog is to obey until another command is given. So he should heel until told to break, or if you have a 'go ahead and sniff every tree you see' command use that.
You may need to start off a few walks with this method before they get it down pat.
"We [the AKC] have gotten away from what dogs were originally bred for. In some cases we have paid so much attention to form that we have lost the use of the dog."
--Former AKC President Kenneth Marden
Inside me is a thin woman trying to get out. I usually shut the bitch up with a martini.