If you have a doctor, I would start there by asking that person if there is someone they would recommend. It may take a few attempts to find someone you're comfortable with. The first session or 2 will be around both of you figuring out if it's a good fit. It may not be. Most therapists have a bio describing their approach to their practice and their beliefs.
Remember, if you meet a therapist and you aren't feeling it isn't a good fit, that's ok. There is nothing wrong with you (or them), it's just not a good fit. Be honest in your feelings, and don't worry about disappointing anyone in the process. This is about you and what's best for you.
If you go by your GP's recommendation, do not think that if you don't get along with them, that you won't get along with other therapists, or that there's something wrong with you. My GP suggested someone in the same building, and they... were not great, for me. The therapist I found on my own (through looking at reviews and whatnot) was much better.
Remember, if you meet a therapist and you aren't feeling it isn't a good fit, that's ok. There is nothing wrong with you (or them), it's just not a good fit. Be honest in your feelings, and don't worry about disappointing anyone in the process. This is about you and what's best for you.