First, you should decide if you want a male or female. Males and females are similar in many respects but there are marked differences between the sexes that you should be aware of.
Males are larger and heavier (24-26 inches at the highest point of the shoulders and 65 to 90 lbs). Females are somewhat smaller and lighter in weight (22-24 inches in height at the top of the shoulders and 50-70 lbs). Secondary sex characteristics should be pronounced for males and females, e.g. a male looks like a male with pronounced masculinity and a female should look feminine with more delicate features. Females will also have a season twice a year. If you choose a female and do not wish to have puppies, then it is recommended that she be spayed. The differences in the sexes in puppies is not as pronounced as in the adult dogs.
Have some idea what you expect from your new addition so you can inform the breeder. Let him/her know if you want a companion, show dog, or a competitive performance dog. No matter what the function you desire in your puppy, all puppies in the litter will have the same bloodlines. Most well-bred litters from ethical breeders are bred to emphasize the health, character, and trainability of every puppy in the litter.
In the search for your puppy, you want to observe the puppies together at first. A German Shepherd puppy should have, first and foremost, a good temperament. They should be inquisitive, outgoing, and unafraid in his advances towards everything and everybody. They will also demand and exhibit affection without inhibition.
Many times puppies will single out one of the litter to pick on. This does not mean this puppy is defective in any way. Take this puppy aside and he will usually assert himself when he is away from his littermates.
Do not select a shy puppy. You do not want a puppy who is afraid of you, or runs and hides. This type of puppy is afraid of people, places and things. Do not be sympathetic; if you owned one, you would be embarrassed by its lack of true German Shepherd character. The definition of the ideal German Shepherd temperament can be found here - The German Shepherd Dog Standard.
What color should you choose?
Color is not a major consideration in choosing a good German Shepherd, as long as the pigment is good. White is an undesirable color and is a disqualification in the AKC confirmation ring. Most companion puppies are sold at 8 to 16 weeks of age. Puppies generally are not ready to go to a new home under 8 weeks of age.
What guarantees you can expect with your new puppy are between you and the seller. If there are hip and elbow guarantees implied in the verbal contract, make sure they are also included in the written contract.