First, you must locate a professional breeder. Breeders can be found through breeder directories (available at your local veterinary clinic, or book store), through referrals from friends, the professional sector (such as groomers and dog trainers), or on the internet.
How do you determine if they are professional or not?
Use common sense.
Is their facility clean? Do they seem knowledgeable? Is it a planned breeding? Is the breeder familiar with the bloodlines of his dogs? Does he know how the bloodlines he is breeding will mix, and what kind of temperaments they will produce?
For example, if you breed a German Shepherd dog from lines which generally produce dogs with soft temperaments… with another line which may tend to have weak nerves…. what will the off-spring be like?
You can usually guess, but it’s even better if you are in a position to talk to several breeders who know what the siblings to the stud or bitch dog you are considering. Once you’ve selected the breeder and the litter you have decided to choose from, the next step is to select the specific pup from the litter.
Personally, I have questions as to how effective puppy testing actually is, in the long run. If you’ve selected good bloodlines, and a quality breeder, you’ve already taken care of 90% of the factors which will determine whether or not you will end up with a good dog.