The age appropriate puppy class is a great idea!! They typically run only for a series of weeks and you can always re-enroll them in a second one or a starter obedience class for additional exposure. At home, I would try mat conditioning to teach a dog or puppy to be less reactive. Taking the puppy places and exposure to new positive experiences is also necessary if you want to be able to take your dog into new situations they need to be de-sensitized in a positive fashion to new places, sounds, sights, etc. However, if you are out with your dog and there is something going on that you think will completely overwhelm your dog...leave. On the other hand, if there is a person in a wheelchair, or who is really tall and they stop to admire your dog---- then giving that person a treat to feed your dog is a good idea (if your dog isn't freaking out). Some trainers do not want their dogs interacting with people when they are out and about with their dogs and I don't really understand why. That person in a wheelchair, a really tall person, that kid with a crutch holding a broom or on a bicycle....see them as training or conditioning opportunities and ask them to give your puppy a treat or two!