You might think it's not worth troubling your dog with this lesson. Your dog almost constantly comes when called, so why waste time, correct? Wrong! "Come!" is among the most important commands a dog can know. When he obeys, you accomplish total control over him. When he is not taught, a dog would come because he wants to. Sooner or later, he would refuse. You will call him one day but he will keep on going and endanger his life in a fight or under a truck.
Begin establishing a positive practice early on by calling your dog to “Come” forfeeding, to Come for his every day brushing or other activities. When he obeys, praise him richly. Never, never call your dog to “come” for a lecturing or discipline. He must connect this command with pleasurable experiences.
To start training, tie a long leash to your dog's collar, and place him in a Sit-Stay position at your left side. Hold the leash using your right handand move away from him as far as you can go without pulling the leash tight. Face the student, call his name, and command "Come!" When he does not start toward you, give a light jerk on the leash to get him going. Praise him lavishly as soon as he gets to you. Practice every day, until the dog comes readily no matter how far you let him out on leash.
Later, let him off leash in a fenced in yard or some place where he can not run into traffic. If he keeps on going rather than obeying your command, turn around and walk away from him. Perhaps he prefers to romp; perhaps he's teaching you, and would be so frustrated when you do not chase him, that he will change his mind and come back. When he comes, do not forget the praise.