I'll wholeheartedly second Upphew's links. The best and sometimes safest way is to contact a proper breeder of your specific preferred breed, see their puppy list, and visit the breeder. Those pages ^are a great place to start.
Breed organizations often also have a rescue list for adult home-changer dogs, if you prefer an adult dog.
In addition to finding out all that you can about that particular breed (and I mean
all; the good
and the bad), also familiarize yourself with the puppies parents' info, so you'll know you're getting a healthy puppy both physically and mentally.
A friend of mine has a pomeranian (from one of those proper breeders in the list), and has been very happy with her choice, after having bordercollies earlier: a Pom being quite low maintenance except for constant brushing required, they're fast learners, easygoing, generally great with kids, but many Poms are also a bit vary of new things, dogs, people; and some individuals tend to be a bit yappy.
With basic training, they'll make nice, fun companions. And hey, my friend has trained their Pom to compete in agility and obedience! So with enough info, enthusiasm and training, anything is possible for almost any breed.
And goes without saying but I'll say it anyway: avoid any puppy mills, possibly imported puppies (often from the east of border..) by shady sellers, and anything that sounds too cheap/a lot below going rate for that breed, etc.
If you're not interested in going to dog shows, naturally you won't need a showdog pedigree for the puppy, but health is still just as, if not even more, important. A good breeder will be interested in (and often expecting to) meeting you personally before fetching the pup, and willing to give you all the information about the sire's and bitch's backgrounds etc.
I've had shepherds myself, but it is just as important with smaller breeds to make sure you have a happy, healthy, vaccinated and vet inspected puppy to get the best possible start for the both of you.
Joha mie sanoi, vaikken mittää virkkant.
