To train a German shepherd to attack on command, the owner must form a bond of equals with the dog rather than a master/servant relationship. The dog must act autonomously as well and not depend on the handler for commands. Dogs should be trained to protect people in real-life scenarios. Nothing should come across as staged during the training process.
German shepherds trained as attack dogs should exhibit a personality that is basically stable, well socialized and quick to learn. Experts recommend socializing the dog when he is a puppy so that he receives a clear understanding of what constitutes an actual threat. Puppies should interact with as many dogs and people as possible. Dogs that are not socialized may bite someone out of fear instead of protectiveness.
Teaching a German shepherd when to bark is the first step in showing him when it is appropriate to attack. Encourage the animal to bark when strangers approach the door, and show him approval by rewarding him with a treat or affection afterward.
Introduce the dog to the boundaries of the property. Do not permit him to bark at anyone who is outside the property line, and never allow him to chase anyone to ensure he is achieving his full potential as a watch dog.