Training & Teaching a dog "come"

Have an assistant help you train dog to come and sit at one end of the room and you should sit at the other end. In turns call the dog to "Come." Always use a happy and comforting tone of voice. Then, use treats to lure your dog to come. Make the idea of obeying the "Come" command fun and desirable. Once you have taught your dog that it is enjoyable to "Come" try calling him randomly through out the day. Reward him generously if he comes. It is vital that you only give command once.
As soon as your dog reliably comes on the first call it is time to move outside with him. Put him on a long leash and begin walking. Command him to "Come" and if he responds reward and praise. If he doesn't come on the first command you can gently tug on the leash and when he returns to you reward him. Continue to repeat until consistent. Now repeat the fourth step with a longer leash and distractions. In your back yard or other enclosure remove the leash and command to "Come." If your dog does not obey immediately do not give the command again. Simply ignore your dog while doing something interesting. When your dog comes to you to investigate put him back on the leash. And review the earlier steps for a few training sessions before trying again without the leash. The command "Come" should always be understood as an enjoyable experience. Do not use the command if you intend to punish him. If you must punish then you go to him. If your dog learns to associate the command "Come" with something bad it will put your whole training program bad horrendously.