Once you have chosen your breeder put your name down on their waiting list for a puppy from a future litter. Be aware that you may have to wait up to a year as good breeders will only have 2 or 3 litters in any one year. However, it is well worth waiting for a quality dog.
Some pointers for choosing your puppy:-
look at all the litter, are they alert, playful and happy? check the puppy's eyes and nose - are they free from discharge? are there any signs of diarrhoea - check the back end for faeces are there any obvious signs of disease such as a cough? has the tail been docked? - this is now illegal in the UK and most of Europe are there any obvious signs of deformity? is the coat clean and shiny?
pick up the puppy with both hands. It will struggle for a very short time but should then settle in your arms. If it doesn't settle, choose a different one.
lay the puppy on its back and keep it there for 30 seconds. Look for one that will do this without fighting or showing any signs of fear. If the puppy tries to bite you in order to get itself free then discard this one.
If you require a puppy for Show purposes and you are not experienced in the Breed follow advice from the breeder or let the breeder choose one for you. After all, it is in his/her interest to pick out a potential Show winning puppy for you. Please be aware that as puppies grow they change so much very quickly and one that has potential to be a good show dog as a puppy may not grow up to be so.