The best time to begin training is about five months of age. A correction is an act you take just as your dog begins to misbehave. To be properly executed, your dog should be wearing a properly fitted chain collar and there should be slack in the leash. With a positive motion snap the leash in a side-ways direction toward your self and then release the tension on the leash . This should be a single quick snap and release, if your dog continues to display poor behaviour after a correction, repeat it with slightly more force.
Timing is everything.
Your dog will not relate to a correction to his disobedience if too much time passes between the two. You must correct faults immediately within seconds as they occur. A dog does not relate a bad behaviour that happened in the morning to a correction given for that behaviour in the afternoon. If your dog disobeys you, it may not be a direct challenge to you as the leader. He may not obey you due to factors such as illness, hunger, thirst, heat exhaustion, or a nearby female that is in season.