Start by figuring out what you are looking for. If you are going to spend the energy, time, and finances on seeing a therapist it's important that it be a sustainable relationship. This means that you want to fit this into your life without too many obstacles, such as distance, cost, or fit of the therapist.
Look specifically in these areas:
Finances and insurance:
How often would you like to see a therapist (weekly, bi-weekly, or monthly), and what is your budget?
How important is using your insurance?
Location and transportation:
Where is convenient for you to meet with your therapist?
Is public transportation or available parking important to you?
Traits:
Gender – does it matter if you have a male or female therapist?
Ethnicity – is there a culture, race, or ethnicity that you want them to be? Or, at least that you want them to have expertise in?
Faith affiliation – is it important that they are a Christian? Or not a Christian? Or not actively offering therapy in another religion?
I've included articles below with more detailed information on each of the following topics:
Areas of expertise:
When I help people find a therapist I go to be my database, which has dozens of columns of areas of expertise. It’s a simple phrase (adoption/foster care, anxiety, chronic illness, grief, trauma, pregnancy, career, depression, etc.). One of my favorite websites for getting info on therapists is PsychologyToday.com because they have a list of therapist specialties, and you can sort by areas of expertise. Therapists also include these on their website.
What area do you want your therapist to be versed in? Rank the importance of each of these items. Which are essentials that you aren’t willing to compromise on? You won’t find the perfect therapist (unless you are able to scientifically engineer a human and design their life experience, and if you are – please share!). For the rest of us, we will need to know our non-negotiables and also get comfortable with some degree of accepting the therapist as they are.