Asking around, primary care and other physicians you have, therapist, online research. You can also check with the state medical board for the current standing of their license and any complaints or grievances filed. They may look fine on paper but I typically won't know until meeting with them. A pdoc I had suggested interviewing any new provider for their beliefs, office procedures, how to get a hold of them for med changes and do you have to come in every time for dosage adjustments, and any other questions or scenarios you've encountered in the past has been the only way to tell; it gives you a better idea of what they are like up front and if they are open, can communicate with you, if you feel comfortable with them more than what is on paper/online. You don't even have to tell them that much about yourself in the first meeting, you're looking into them; it's about who you're comfortable with and a referral can't tell you that. I would look into credentials but then interview. Good luck in your search for who is best for you!