Doing quick sessions at first offers more benefits than starting with a long walk, especially for puppies and easily distracted dogs.
We have found that dogs do best with a gradual approach of giving them guidance with the harness and then time to rest after they respond. Every time you move your leash, your dog feels the harness. A short pause after your dog responds helps him understand that he responded well. Repetition and consistency develops body cues when only slight movement of your leash is needed for a good response.
Also, using different leash methods distributes the affect on your dog’s sense of touch.