How to select a pup from a litter:
Selection of the right pup to meet one's particular expectations is extremely important. Making a correct choice can improve the odds of producing an excellent retriever.
The first and most important point is to consider a genetic selection process rather than trying to select a promising prospect from a particular litter. Focus not so much on picking a pup, rather pick the litter based on quality bloodlines of the parents.
The pups should all be quality choices. Six weeks is just too young to choose particular character in a puppy. Coat color is the only choice possible at this stage.