You’ll need to first properly fit a pinch collar and get a leather 6 foot leash. If you feel your dog is a very “soft temperamented” dog, then you can use a regular training collar, or sometimes even a flat leather buckle collar. But in most cases when people have trouble with their dog [pulling->walking on a loose leash] on the leash, the proper use of a pinch collar is the easiest and most humane way of going about fixing the problem.
Hold the 6 foot leash at about 1/3 of the way down, and with two hands, pretend to glue it to your waist area, as if you were connecting your hands and the leash to your belt buckle. As soon as the dog starts to run forward, you need to do a sharp right-about turn, and RUN the opposite direction.
The dog will automatically receive a sharp snap when it hits the end of the leash. You need to do this back and forth, and within about 2 minutes, the dog will realize that if he stays close to you, he avoids getting left out to hit the end of the leash. If he chooses to ignore you, then you teach him that you’re not just going to stand there like a dumb pole, or a tree, but rather you’re going to “get out of Dodge” by running the other way.
When the dog starts staying with you, you can praise him. Soon, the dog will learn that it’s really his choice. If he wants to, he can go all day and get nothing but praise. He also learns that you are a more immediate concern than any of the other distractions. Again, if you have a large breed dog (or one who behaves like a large breed dog!) I would definitely recommend getting a pinch collar.
The pinch collar will make your corrections motivational (i.e., have meaning.) If, when the dog hits the end of the leash (as he does now) it doesn’t feel uncomfortable…. there’s absolutely no reason for the dog to stop doing it. The pinch collar is like driving a car with power steering.