I dont' know what the "proper" method is, but here's what worked for my pup. I had a similar problem with my lab at the same age. I would tie a long leash to her and let her feel like she was loose. Let her get about 10-15 feet or so away and try calling her name. If he/she ignores you, tug the leash at the same time as commanding her with a stern voice to come. You need to get her attention back to what she's supposed to be listening to. Before long he/she will relate to the command call by your voice. EVERYTIME she comes back give her/him[:-]a treat. Work with the dog for the 10-15 feet until it has that part down then extend it some more.