Go to dog shows. Check the Internet. You need to educate yourself first, and prepare your house for your new dog. You do not have to limit yourself to a purebred dog. We will address crossbred dogs later.
Puppies are irresistible, but they're also an enormous amount of work.
You get the benefit of helping to shape your dog's behavior during part of her critical learning period, which occurs between 4 and 16 weeks of age. But you also have the housebreaking, chewing and wild teenage years to contend with. An adult dog is full-grown and already set in many of its behaviors, so you know how big it will be, how it will look, and generally how it will behave. However, they can be more challenging to train since they are already more set in their ways, and are beyond the highly receptive 4-16 week learning period. Find a good source for your dog.