So, the BIGGEST socialization mistake a lot of Dane owners make is to take their puppy and let people, dogs, etc. intimidate, scare and flood it. Not on purpose of course, but by not knowing any better! Socialization is about being in the world and having GOOD things happen. Make as many good things happen as possible! See a kid? Treat! See a bike? Oooh good dog what's that bike over there! Here’s a lil treat! See people? Sit! Good dog, treat! Don't let people come up and squeal and hover and scream and be annoying, not yet. At first strangers need to be introduced at a distance, just enjoy people watching. When people approach explain you are training- no petting right now. Your puppy can interact with people AT Home and calmly. After puppy confidence is built, introduce other distractions too. Somebody bouncing a ball, opening an umbrella, riding a skateboard etc.
Focus on positive exposures in the world more than greetings. You want your dog to ignore things in the environment, not be so amped up or scared by them that they jump, run, cower or show rude greeting skills.
Walk over wood chips. Grass. Gravel. Through tunnels, over bridges. Along the shoreline. Drive through an automated carwash, maybe with some cheeseburger bites :). Trim nails weekly starting today! File them daily focusing on positive toe touches. Brush puppy’s teeth. Touch all over their body. Play sounds on your phone (thunder, babies, etc.). Make the world no big deal.
Add a lil more each week, go in a store one week look around leave in 5 minutes, next week greet the cashier walk around leave. Week 3 push a cart in this store. Think of it as building blocks.
This is the approach I try to take with all our puppies and those I have done with with are amazingly social and friendly.