You can leash train a puppy by first finding a well-fitted collar and then actively training the dog using positive reinforcement. Finding a collar is an important part of leash training, because an ill-fitted collar will either hurt the dog or fit over its head and allow the dog to escape. To actively leash train a puppy, you need to practice walking it on a leash; a puppy will never be properly leash trained without a lot of practice. In addition, using positive reinforcement lets the puppy know it is doing something right and should repeat that action for further praise.
Start to leash train a puppy as soon as possible, especially if you have a large breed. Large breeds can more easily pull on a leash and go wherever they want, making training difficult. To begin, get a well-fitted collar for the puppy and a short leash. The collar should be checked on a regular basis to ensure the puppy has not outgrown its current setting. You should not be able to pull the collar over the dog’s head, but neither should the dog be pinched at its neck.
Hold the leash in one hand and walk in a straight line. If the puppy begins to wander, reverse your direction, but never jerk or pull the puppy. Let the dog know that you wish for it to follow you by having a “follow me” attitude and walking with a purpose. If the dog begins to pull on the leash, immediately stop walking and stand still to let the dog know that pulling does not work with you.
Remember to use positive reinforcement to leash train a puppy. Negative reinforcement, like jerking the dog around on the leash, yelling at it, or punishing it in some other form, often makes the situation worse. Giving the puppy a treat, exclaiming about how good the puppy is, and petting the puppy enthusiastically are all forms of positive reinforcement. Positive reinforcement should be used whenever the puppy does something the way you want, especially if it's the first time the puppy performed that action.
You have successfully leash trained a puppy when the leash can be slack but the dog is not lagging behind or pulling ahead. The puppy should be interested in where you plan on going and always follow, even when it smells something interesting. Some breeds of dogs learn new things quicker than others, so have patience when you start to leash train a puppy.