Where do their breeding dogs and puppies live?
How they they socialize them?
How long have they been doing this?
What pediogree will the puppies have?
Will they be dewormed,vaccinated,microchipped?
Why did they breed thos two dogs?What was the reasons,what they wanted to get out of this litter (reputable breeder should be able to answer why he chose that male instead of that one).The best answer to this would be not because he lives across the street,but because he has something that my female doesn't,so I'm improving the breed and getting puppies that are better than their parents.
How and with what do you feed the puppies and the mom?
This is first that comes to my mind.
Look for a responsible breeder.I think I saw a thread about this on dogforums.com general dog discussions,that was a sticky thread.Look it up,I saw some useful stuff there.