Hi Amanda. Getting a new puppy at 4 months of age comes with a built in advantage and disadvantage when it comes to potty training. The advantage is that your puppy is at an age where the physiologic ability to postpone elimination is firmly in place, the disadvantage is that your puppy has also become accustomed to his previous potty routine. It may sound like an over simplification but the quickest way to train a puppy to potty outdoors is to leave him outside. I know that this is not practical or desirable for most people but you must have your puppy outside as much as possible until you reach your goal. Trying to change your puppy's habits by only taking him out when you think he needs to go will be frustrating. Another suggestion is to interrupt every activity- eating, sleeping and playing before your puppy has stopped and immediately pick him up and get him outside. Then stay outside until elimination has occurred and pour on the praise. This usually will work better than trying to get him outside once he has started elimination. In the beginning it is also a good idea to go to the same area outside every time.