For starters, ask around. Ask your friends and people at work where they get their vehicles serviced. If they're happy with a certain repair facility or technician, then give that repair facility or technician a try. If they do good work and your satisfied with the results, then you've solved your problem.
If you don't get any specific recommendations or are reluctant to ask others for their advice, you can always look for the "ASE" logo. The National Institute for Automotive Service Excellence conducts competency tests in many different areas of auto repair. To become certified in a repair specialty, a technicians must pass a tough written examination as well as meet minimum experience requirements. What's more, the technician must recertify every 5 years to keep his credentials. Those who pass the exams receive a wall certificate listing their areas of expertise, and and ASE emblem that can be worn on their uniform. Technicians who pass all eight ASE automotive tests become certified "Master Technicians."
Having a technician who is ASE certified work on your vehicle is no guarantee he won't foul up or try to cheat you. But your chances are probably better with an ASE certified technician than someone who doesn't take their profession seriously. Most ASE technicians see themselves as professionals and strive to do their best.