Focus on the first 20 Weeks.
In the first 20 something weeks of a puppies life its brainwaves are in Delta. This gives the puppy the ability to learn from its environment without filtering through reason and thinking. They basically download, accept and adapt. An example is a puppy born in a puppy mill will accept its environment, it will adapt physiologically by having higher stress hormones and being less active. This is not good for a puppies health but needed for dogs going to survive in cages. I have been unfortunate enough to visit such places and the dogs are dull eyed and not healthy.
This stage of life can also be used to teach puppies the joy in life, and how to adapt to a stressful environment in a positive way. I have 2 Schnauzers, the one was exposed to fireworks at a young age and has no fear at all, in fact he likes watching Ivan shoot of starbursts and crackers. My other little girl was never exposed in the first 20 weeks, my bad, she is terrified, she runs and hides at the sound of any loud noises. The interesting thing is that we shoot fireworks all the time and one would think that she would get used to it, I think she is better but she is still hiding.
The secret to walking a pet on a leash is to get them to follow you, don't drag. We show how a training chain works because many people have no idea and cause more damage than good. Be patient, don't drag. It takes time and learning patience from your puppy is a precious gift from him to you.