Hi There.

It depends on what you are looking for to be honest.
Are you looking for a vet with a more holistic approach, particularly their stance on vaccines and feeding?
Do you want the clinic to be AAHA Certified?
http://www.aahanet.org/
We get a variety of questions that range from price inquiries to philosophies.
When you narrow it down to a few clinics that you like, ask if you can pop by (with your dog) and meet the staff.
Personally, I like a vet that has a down to earth approach, that will discuss ALL options with you, etc. I also prefer a practice that has one or two vets so you consistantly see the same doctor. That is why I work for the veterinarian I do.
Some people prefer a big animal hospital with specialists on staff.