Finding a mechanic to fix and maintain your golf cart is almost like trying to find someone for your car/soccer mom van/SUV/truck/hybrid or whatever vehicle you have. You want to find someone that is good and someone that you and others around you that can trust fully.
To start finding one, you can ask your friends or golfing buddies about people that they used in the past. If you are new to the area, you can always ask the local pro shop or ask a random golfer on the course for a few ideas. Once you have found a shop that seems to best fit you, make a call to the Better Business Bureau. The BBB will be able to tell you if the business is a member and/or tell you about any complaints filed against the business. You can perform the same check with the American Automobile Association (AAA) or with the National Institute for Automotive Service Excellence (ASE).
It is also a good idea to find out the location and the hours of the shop and if you could pick up the cart before/after work. When you finally go into the shop, always get a clear explanation about the work that is being done on your golf cart. Also ask for the warranty of the work and find out if it covers parts, labor or both.
Mark