Big surprise!? Dog training is less important than socializing your dog! And for the German Shepherd Dog breed, comprehensive socialization is essential because this dog has been bred to react to the faintest unfamiliar stimulus that could threaten the herd that the GSD is meant to guard. For a family dog, the herd is your family.
Now if you don't systematically socialize your dog then this dog will feel alarmed (and thus stressed!) upon so little as a neighor two roads away mowing his lawn - unless earlier your dog has seen and heard the neighbor mowing his lawn while with you and staying calm. What your dog got accustomed to in the right setting will not alarm your GSD. Everything else will.
The widespread lack of comprehensive socialization is the reason why many people (including city officials) consider the German Shepherd to be barking too much, or even to be an aggressive dog. So make sure that your German Shepherd won't cause needless restrictions of any kind: Socialize your GSD to the MAX!
Many dog owners claim "my dog is very well socialized!", or worse they believe "my puppy is SO sociable, he greets and plays with every person!" - but in most cases I get to know, the dog owner couldn't be misled more:
Mark this and remember forever, recall it in your sleep: There is a HUGE difference between the impression "very well socialized" and systematic socialization! I've put a detailed socialization report in the Puppy Development Guide - Puppy 101 (it even includes Checklists). You can use all of that for the adult dog too, in fact if you haven't done so, it's even more important for your adult dog!
Every day, your first thought should be: "What socialization can I provide for my dog today?" And only your second thought should be: "What training repetition can we do today?" - Don't worry if your first thought of the day is your spouse or your children (or the taxman), just make sure it's not: "Which cool dog trick can I teach my dog today?"
Only once you're sure that dog socialization is your first priority, give the right dog training some consideration too.