How to Pick Out A Puppy? Tips?

I'm going to look for a puppy tomorrow (golden ret.). This is my first time doing this and am wondering what the process is in picking the right puppy for me? What Do I look for in it and how it behaves and it's health? What questions do I ask the owners? I want this to be a good choice as this dog will be with me for a long time i hope so I want to do the right investigating. I wish there was a car fax for dogs. lol. Any help much welcome.