If you're looking for a good health clinic, check your insurance provider list first. Many HMOs and similar providers publish lists of health facilities in your local are where your insurance is accepted. Once you've located a good candidate, it's a fairly simple process to visit them and check them out.
One way to find a good local health clinic is to network with friends and family. Generally, they can tell you where to find a facility in your neighborhood and will be perfectly willing to rate it for you, so you dont have to waste time reconnoitering clinics that won't fit your needs.