When you have a scared puppy that is fearful of people, keep up your socializing efforts, but with a twist. Your new goal is to work on making people "no big deal". To begin making people "no big deal" take your puppy for a walk and simply walk past people without stopping. If the people want to stop and pet puppy, tell them "No, sorry he's in training right now." If your puppy barks at people, ignore the barking and move away to a place to give your puppy distance from the people. Slowly work at lessening the distance. Harness the power of "cookies" to speed up the process! When your puppy notices a stranger approaching, call your dogs name and when he looks at you, say "yes" or click a clicker and reward with your puppy's favorite treat. This accomplishes two things: First, it helps with your training your puppy to pay attention to you even when distracted and second, it associates strangers with yummy treats. With several sessions of practice of making people "no big deal", your puppy should start to feel more comfortable with people coming and going around him. Continue not allowing people to greet your puppy until you start to see him getting interested in other people and perhaps begin to want to go up to people and greet them.