do some research and know what you want first.
what kind of therapy, what kind of T.
when you call, ask if the person is accepting new patients/clients, check out the fee to see if it is in the range you want, you can ask if they treat your symptoms/diagonsis, then ask to schedule an initial interview meeting where you can ask more and see how you feel about the person.

here's a site that might help: www.guidetopsychology.com