Ask other parents who have used a math tutor about their experience and who they would recommend. If they have had a good experience, chances are you will as well.
Talk to your child's math teacher for help in finding an appropriate math tutor for your child. Often times they keep lists of tutors in the area.
Call your local school system for a list of competent and experienced math tutors. Many school districts have a prescreening process for tutors they recommend.
Get information from local colleges and universities about math tutors they have available. College students use tutoring to supplement their income.
Visit your local library to find out about their tutoring programs.
Speak with math teachers at your area High School. Many advanced math High School students use tutoring to fulfill volunteer service hours. In many districts community volunteer hours are a graduation requirement.
Look online or in your Yellow Pages for tutoring services in your area. There are many companies who offer after school tutoring programs.