What can I do to get my dog to play/get along better with other dogs?

I have a 1.5 year-old labrador retriever that doesn't know how to play gently with other dogs. He isn't aggressive or anything, he just gets way too excited and starts to jump and trample on the other dogs, which has caused him to not be accepted at dog daycares. I even have to keep him and my 14 year-old dachshund separated most of the day because anytime he sees her he starts to run and jump and trample her and he doesn't understand that her snapping at him means that she doesn't want to be played with, he will just keep doing what he's doing and nothing that we do to try to correct it works. I can tell he means well, he doesn't bite or scratch or anything, he just gets too excited.