Qualifications. I'm not sure how it works in the states, but in Canada, there are provincial certifications and national ones. The provincial cert you can get in BC is just two weekend courses, making me sort of distrust anyone who just has that. The national one requires at least two years of post-secondary education and so is much more valid.
Also look for experience. Try and find someone who has been doing this for years. (Although, at the same time, not someone who's TOO old and whose education wouldn't be very updated.)
