It's a little late to suggest what I'm suggesting, but this is good for people with very young pups, for folks who know breeders, or for ones that rescue pups at tender ages where the dam may not want to nurse the pups any longer.

One thing you can do is expose a puppy to all sorts of noises. Find noises that resemble motors, claps, glass shattering, whistles, sirens, screams, foot steps, knocking on doors, gates closing, strong winds, cats, other dogs barking and growling, crying, air planes, thunderstorms... etc.

You might ask why? but a lot of neuroligical development is going on between the time a pup is born and when they are 8 weeks, coming home with their new parents. The more exposure the litters or pups get, the more sound they will be around strange noises, and new situations. If they have heard just about everything before, they will not be easily startled, or become anxious due to loud noises. This makes for a stable, sound, well adjusted dog in the long run, when combined with proper training, exercise and of course a lot of love. Dogs are social creatures, so they should be exposed to just about every situation, even if they are not ready to hear the real deal out in the world.