[header] How to train a german shepherd to be a guard dog [title] Socialize your german shepherd when he is a puppy. [step] In order to have a well-trained guard dog, you will need to start socializing your german shepherd from a young age. Puppies are more receptive to new things until they are about 18 weeks old. 
During this time, the things that they see, hear, and smell are less frightening. It is important to make sure that your german shepherd puppy is well-socialized during this time so that he will confident rather than anxious or fearful.