I don't know much about labs but here are some suggestions you might try. Find a good breeder with references.Look ata second breeding of particular parents then contact the first litter owners and see how their dogs are like. Chances are the second litter will also be as good or bad as the first litter. Try to go to the breeder and see the parents and chose your own pup, an apple will not fall far from the tree.

If you find the breeder has multiple litters of the same parents or alot of dogs, look more closely. You may be looking at a puppy mill. Although some nice dogs have come from puppy mills, I wouldn't support them. More chances of genetic defects cropping up. So, if you can, contact the original breeder. There are middle men out there and they act as an agent of puppy mills.

Good luck. As long as you do your homework, I'm sure you'll end up with a nice dog.