We think the best place to get a Golden Retriever is from people are very involved with their dogs which may mean they who compete in some facet of the sport. For some reason, we are called hobby breeders. I guess getting a puppy from a passionate breeders has the wrong connotation.
Golden Retrievers are active in conformation, hunting, obedience, agility, and tracking. If the breeder is competing and involved in one of these areas, it is more likely that he or she is breeding to produce dogs that will perform well in these areas; in other words, breeding better Golden Retrievers. And these people are spending a great deal of time with their dogs so temperaments and longevity are important to them.
And you should expect that good breeders will have some accomplishments to point to. Don't be fooled by the people who talk 'Championship lines'. Ask how many of their dogs have earned titles in the last 12 or 24 months at AKC or UKC sanctioned events; 'international titles' don't count.
Be concerned if your Breeder does not plan to keep a puppy out of the litter. When you find a person breeding dogs but selling every puppy, it may be a red flag they may be doing the breeding just to make money. If this is the case you need to be concerned about where they invested the time and money in making sure it was the best breeding they could possibly do. If the breeder is keeping a puppy, you can be more certain that they will have done their best.
There are times a breeder cannot keep a puppy. But when you talk to them about this you'll probably find it very easy to tell those that are just trying to make money from the responsible breeders who want to improve the breed.
Be alert if the breeder owns both the brood bitch and the stud dog. In breeding good dogs, it is extremely common to either ship the mother (dam) or to have semen from the father (sire) shipped to the breeder. There are hundreds of stud dogs in the country. If, with all those choices available, the breeder chooses to only consider their own dogs, you may want to ask why.
Be worried if they say they are a breeder of "rare English creams" or special dogs from Europe. This is a marketing ploy as there is no such thing.
What types of guarantees and contracts do they have? Most reputable breeders will use a written contract and they will include in that contract that they will take a dog back at any age for any reason. This is not to say that they will refund your money. But they will provide or find a home (in other words be responsible for) any dog that they have bred for the life of that dog.