Just start by googling various martial arts schools in your area. Then, call the school and speak with the instructor. Ask if you can come in and observe the school and the other students. Ask to sit in on a class. You will be able to tell right off the bat if the instructor is warm, open, and welcoming. All of which are super important.
A good instructor will be more than happy to have you come into his/her school and take a look around, watch a class, whatever. And they will be excited to talk more with you when you get there.
I actually did this when I was looking for a tkd school. It made all the difference in the school I ended up going with. I was not interested in working with an instructor who was offish.
The vibe of the school and the instructor is very important to me.
Best of luck to you!!