I'm on my 5th German Shepherd and even this time around I'm still learning stuff. A few things I just picked up on this go around:
Don't make feeding time about feeding. Make feeding time about obedience. My dog does not eat without performing some sort of obedience training. This has definitely made her very obedient. I prepare her food, do some gesture eating, and then do some obedience with her before I put the food down (early days) or before I give her the command she can take her food (now). At first it was things like sit and lay down. Then it was take it or leave it. Eating gentle from my hands (so she could learn to take treats easier without biting off fingers as well as to avoid food protectiveness) , and now we have moved onto prolonged stays of a minute or two. If she acts up like jumping, barking, or misbehaving, the bowl goes back onto the counter and we try again in 5 minutes. After 15 minutes I was told to skip a meal but my pup has never gotten that far. Prior to this, feeding time was feeding time. Never realized how much opportunity my family was missing by just putting the bowl down for them to eat. All of her training has started at the food dish. And she is extremely obedient now.
A Front hook harness helps with walking. You attach the leash to the front of the harness instead of the back or the collar. When the dogs try to lunge or pull, by nature, the harness causes their body to twist and they are unable to pull much. I have a 5 month old pup that hardly ever pulls on the harness thanks to this simple tool. Not sure how well it's going to work when she's an adult but we are already working on leash training so I'm hoping I won't even need to prong collar her.
And this I learned the hard way previously but socialization is a major part. Even before they are fully vaccinated. You have a brief time frame up to about 6 months and even sooner that they need to be exposed to a lot of people, a good variation of dogs, and a good variation of scenarios (like swimming if you want them to not be afraid of water) I had a rule where my dog had to meet 15 people a day. From having previous dogs with big protectiveness issues and aggressiveness, I now have a confident pup who does not lash out at any dogs or people and loves to meet new dogs and people without a hint of aggressiveness.