Given that the German Shepherd was bred for herding and guarding herds of cattle and flocks of sheep, barking is your pup's natural way of warning you. At the same time, most Shepherds will bark just because they enjoy it and it burns off some excess energy. While this is all well and good for your pup, by the time he reaches adulthood and his bark hits max volume, your neighbors are likely to be less than pleased.
Keep in mind that you should never try to completely silence your pup, there are times when he still needs to be able to let you know what's going on. Such as when an intruder comes on your property or in your house, when there is a fire, or when he is startled. It is important that you understand the difference between nuisance barking and communicating.
The task itself is to train your dog not to bark unless there is a good reason for it and to stop barking on command. This means you will need a command word; most people just use "Quiet!" as it is simple and effective. Use the same command each time to avoid confusion and use a firm commanding voice without sounding angry. Shepherds respond well to positive reinforcement training methods, but do not respond well to negative training methods such as being yelled at or struck.
The good news is that your furry friend comes from a long line of highly intelligent canines who are easily trained, love to have a job, and are always ready to please their family. As long as you remain consistent in your training, patient, and willing to spend the time needed to train your pooch, he will learn that there are only certain times when barking is perfectly okay.
While it might seem odd, before you can teach your dog to stop barking, you need to teach him to bark on command. This will help set the stage for when you start training him not to bark unless you tell him to or he has an acceptable reason. You really don't need much in the way of training supplies, your supply list should include:
The most important thing you need is the ability to remain calm and keep working with your pooch until he finally understands what you want of him.