TEACH YOUR DOG TO WALK ON-LEASH
The Basic Method: First you will need to teach your dog to respond to a specific signal like, clicking your tongue. STOP immediately when the leash becomes tight or is about to become tight. WAIT 2 seconds and stand still and say nothing. MAKE the clicking sound with tongue.
When your dog starts to turn his head to look at you, PRAISE him WALK a couple of steps in another direction so the dog follows REWARD the dog for following by saying "good boy" or by providing a treat Repeat these steps everytime you want to change direction of when your dog is about to pull. Begin working on this where there are no distractions. Later work on this where there are distractions like cars and squirels and other dogs. If your dog loses concentration it is because he is tired. It is likely that you have worked on training him for too long. Start out with only a few minutes and work up to 5 minutes and beyond. The ability to concentrate can vary with age. As training continues, start giving treats a little less and less often. Every second and third time.