Jocko was a big, strong, beautiful German Shepherd that I worked with back in the 1980's as a security dog handler in Hartford, CT. Jocko was also one of the best trained dogs that I ever worked with. His obedience was perfect and walking on leash was what he did best.
Most dogs are trained with choke or prong collars. Choke collars are very difficult to use correctly and I do not recommend them. Prong collars are more effective but I usually do not use them to train. Instead, I recommended a more positive approach. Done correctly you will not need any type of force to train.
The first step is to teach your German Shepherd to walk with you and not pull. This is accomplished by maintaining a loose leash. Whenever you are holding onto the leash do not let any tension develop. If your dog starts to pull away from you it is common for us to pull back on the leash. This will create more tension and your dog will pull even harder.
Always maintain a slack leash while walking. Start by having him follow the treat at your side. He will learn this is where you want him to be. It's important that when you practice you change directions, speed up your pace, slow down and do frequent stops.
Once you have done this for a few weeks you need to start fading out the trips. As you gradually fade the fears make sure that your leash is always held loosely at your side. Once you fade the fears your dog may lose attention. When this happens quickly change directions to keep your dog's focus on you and where you are going.
Within a week or two your dog should be walking nicely at your side.
Source by Eric Letendre