First of all, it would be ideal to find one who deals with transgender issues. You might be lucky on this point. We have never had more resources available. The other thing to look for is the number of questions a therapist asks. A good one will help you discover yourself. They will refrain from telling you what to do.
Beware of therapists who are sycophants. These are those few who will agree with everything you have to say and sympathize with every woe you share. All of us have some pent up frustration and may demonstrate it in various ways. Not all of these things are real problems. Watch for the therapist to dig down under the superficial problems to discover the real issues you must address.
That's my advice. It's free. And worth every penny.
Cindi.