I have never recommended puppy socialization classes. They miss the boat on so many necessary and more important aspects of socialization and dog owners trying to do the right thing find out later they’ve fear imprinted instead of socialized or left out most of the real things a dog needs to be exposed to and a bunch of other dogs is pretty low on my list.
I’ve seen the consequences of this down the road. This pdf is what I call a John Wade’s Puppy Socialization Cheat Sheet. It gives you an idea of what I recommend you expose your puppy to from 3 to 12 weeks of age. They may seem silly but I’ve been training for over 20 years and have seen enough and read enough research papers to know that a wide range of sounds, smells, sights and textures experienced in a pleasant or neutral manner before 12 weeks of age are what make or break the degree a dog will as an adult be able to share its owner’s life. Doing as many of these things as possible reduces fear and aggression as well.
Click on the following link for your free copy: John Wade’s Puppy Socialization Cheat Sheet