Are you looking for a hunting dog, or a family companion? If a hunting dog, are you chasing ducks and geese, upland birds, or both?
I run pointing dogs, so I cannot help you in the lab world, but I can share some things that have worked for me in terms of picking a pup.
There are a LOT of breeders out there especially in the lab world and when you think about it a very small percentage of the dogs in that breed should actually be bred (with the goal of improving the breed). For me; that rules out any breeder that only breeds within their own breed stock. The odds of one breeder having multiple males and females in the top 1% of that breeds population is not good. I stick to guys that are agressively trying to improve the breed by searching out the best mate for their dog and seeing what the outcome is. Just becasue one dog is great, doesn’t mean their offspring will be. Because of this, I will stick with repeat breedings where the previous ones were successful. Bare in mind, this isn’t going to be cheap, but you do get what you pay for and the purchase price of a dog is not a big deal when you think about the total cost over their lifetime.
In order to find this caliber of dog, it’s easiest to attend hunt tests, or field trials of the type you’re interested in and talk to people. There are some great people in these events and their knowledge about hunting dogs in your area will be invaluable. I’d guess that as you do your research at these events, there will be a few breedings that will rise to the top and be the overwhelming favorite among your areas experts.
From there, chances are you’ve landed on a very knowledgable guy to buy a dog from and I’d let him pick the pup for you out the litter. He’ll be able to best match a pup to your needs.
Good Luck! There’s nothing better than getting a new puppy, and turning it into your dream dog.