Once you have a few prospective tutors lined up, ask each one for a face-to-face interview. After meeting them in person, you'll have a better feel for whether or not they'll be able to work with your child.
Ask the following questions in any tutoring interview:
There are a lot of tutor certification programs. Certification indicates a tutor has studied and passed an exam. While certification is a good indication of a commitment to quality, whether or not a tutor is certified should not be your only concern.
With the Internet, performing an educational background check is easy and relatively affordable. Some sites to consider:
Pick a tutor based on her qualifications and your gut instincts. And always sign a contract.