Puppy Training: Start today. Not when your dog goes to training classes. Literally, today. You can find great guides on YouTube to teach your dog to sit/down/stay/recall etc. Use them. Puppy training does not start and end with a crap six week puppy training course in a room with 6 other dogs. Use your dogs daily allowance of food to train it - don't give them extra treats. Don't use pads/newspaper - it just teaches the dog to go in those places inside and quite frankly is grim.
House Training: Outside every 20-30 minutes. After every nap. After every game. Watch for the warning signs - circling and getting ready to squat. Straight outside. If the dog doesn't pee/poo, bring them back in. Don't let them amble around for ages or they won't learn. Use cue words 'Wee' or 'Poo' or 'Jobs' - start by letting them wee and then say 'wee' (or whatever word you want to use) and then give them a reward once they perform. Within a few days they should learn that 'wee' means do a wee.
Socialisation: Take your dog out in a sling/backpack etc. Do NOT take it out in your arms - it will wiggle free and hurt itself. Show it the world from the sling. Let it see other dogs/cars/busses/wheelie bins etc. Just don't let it's paws on the ground or let strangers pat it until it's had it's second vaccination. Socialisation does not mean just showing them dogs/people/cats, it means showing them the world.
Distance: Let your puppy spend time alone. Leave the room for 10/15 seconds at a time. Don't go back until the puppy has stopped crying. NEVER go back when the puppy is crying (not unless it's screaming in pain and trust me, you'll know the difference). If you go to a dog that is crying, it learns that if it cries you come running. And PLEASE do not let your puppy sleep in your bed. It needs to have somewhere that is its own - at least for the first few months. Letting dogs sleep in your bed from day one just encourages separation anxiety later in life.
People: Do not let people encourage your dog to jump up. They love doing it to puppies. They like it less when it's a 50KG dog doing it. Or even 10KG. It is your dog, not there's - do not be afraid to put in boundaries.
Finally, remember your puppy is a dog. It is not a baby. It is not a child. Treat is like a dog. Don't hold it upside down in your arms to kiss it's belly (FFS to people who do that) and don't hold it under it's armpits to kiss it's nose. It's a dog.
You will spend several days/weeks over the next few months wishing you'd got a cat. Or a gerbil. Or a rabbit. It DOES get better.