Ask around at your place of worship, or check the Spiritual Directors International Seek and Find Guide. Spiritual direction is not a licensed profession in any state or country, as far as I know, so it’s up to you to ask questions and make sure that you feel comfortable with whomever you select as your spiritual director.
Go ahead and interview potential directors: Have they received training? Do they meet regularly with a supervisor? Do they meet regularly with a spiritual director of their own? Are you comfortable with their religious tradition, approach to spirituality, and way of interacting with you? Do they charge a fee? The SDI site has a helpful list of questions to ask a prospective spiritual director.
Take time to pray and reflect on the decision, and ask your potential directors to do the same. If you notice any “uh oh” feelings or red flags as you sit with the decision, pay attention—your intuition might be telling you something that you need to know.