All breeders have their own ways of choosing a puppy. Many of them will choose while the puppy is still wet from birth, but this is prone to problems, a swollen head from a large puppy and a difficult birth will reduce over time and may not be so spectacular when the puppy grows.
Puppies are perfectly in balance at 6 weeks, 6 months and then again when adult.
To get the best animal take the adult.
Then you will know exactly what you have got.
Second choice choose 6 months, third choice and most likely, do it at 6 weeks.
If you are the breeder do not make up your mind until 6 weeks.
Choose a puppy with an extrovert character, not the one who hides in the box. Watch the puppies at play with each other and avoid a bully. Test the puppy for deafness, get behind it and clap your hands, if it looks for where the noise came from then it is ok. How does it move? If it seems to be poor on its feet suspect the animal is not correctly put together (compared to the other puppies in the litter). Do not buy the runt!
Everyone wants a spectacular head and the down face is proportional to the dome on the head.

The more the head looks like sketch 2 the more the down face, however this also means the more the animal could be undershot.

down face very rarely comes as good as this.


This bitch had a perfect mouth.
Remember it is extremely unlikely that a dog with a wrong mouth will become a champion.
Ensure that you meet at least one of the parents. If they don't own the bitch then he may well be a puppy farmer rather than a proper breeder. It is unlikely that he will care about such things as temperament and conformation and will breed to the cheapest dog around.