At any rate, don't select a puppy just because its the cutest one in the bunch. At the very least, watch the litter for a half hour or so, to discern the different personalities. Take advantage of breed clubs . Most breeds are represented by at least one breed club. If you talk to its leaders, you'll learn about the backgrounds of breeders.
Many clubs have a code of ethics, maybe even a specific code of proper conduct for breeders.
If you learn about these from the breed club, you'll have useful information about the breed when you begin to evaluate breeders. Don't worry if a club representative doesn't personally know the breeder you are investigating. Be more concerned with an endorsement of proper breeding ethics, and some form of indication that the breeder has good quality, registered dogs. Breed clubs know which genetic problems are important to their breed, as well as the strengths and weaknesses of their breed. They are the best source of this information.