How Can I Stop my Puppy from Biting 

It's important for puppies to learn to control their bites.  This is best taught at a young age.

Carefully watch your puppy for signs that he is about to grab your hand. Before he can do that, give him a soft toy or a Kong as an alternative.

If puppy bites you before you can give him a toy, make the squealing sound a littermate would make when it is bitten by another pup – "eek" or "ouch". Then quickly redirect the puppy to an appropriate toy that is "chew safe". 

When a puppy can't be supervised he should be safely in his crate or an exercise pen with Kongs or other dog-safe toys that can't be chewed up and swallowed.  DO NOT LEAVE STUFFED TOYS IN A CRATE WITH A PUPPY.  Talk with your breeder and/or vet about safe toys for puppies.

Also, a tired puppy is a good puppy. Be sure your puppy gets plenty of exercise for his body and his brain (but a 1-mile walk or more is WAAAAAAAY too much until the joints knit).  Exercise for 10 minutes every hour or so is better than 2 hours at a time.  Puppies need naps just like babies.

Start training at an early age in a good puppy class in your area.  Puppies of all breeds get your puppy used to other types of dogs.

Based on information supplied by The German Shepherd Dog Club Of America by Cheryl May,