I'm transgender and I want to start hormone therapy. How do I start the process? Do I go into see a doctor or do I talk to a therapist first?

Best Practices: Find a trans-competent mental health specialist who'll be able to assess your understanding of the benefits and risks for you of hormone treatment, and who can then refer you to a trans-competent physician to determine which hormone treatment(s) would be most suitable for you. Familiarize yourself with the current wpath standards of care: http://bit.Ly/nwkqv5.
Both! Wpath guidelines recommend you see a therapist first as per dsm (psychiatric diagnoses) then your therapist will provide a letter you can take to an endocrinologist or any specialist in transgender health in your area (there are not that many docs comfortable with this), or start by asking your familydoc or look at the local glbtq site for a good doc.
Counsel first. Get counseled first. It s a very good ideea. Hormonal therapy will cause some irreversble changes to your body. You need to know exactly what will happen with your body. Then after everything is clear in your mind you can proceed as desired. Take drugs prescribed only by a doctor, do not selfmedicate.