I am a licensed clinician and I'll pass along the two best pieces of advice that were given to me decades ago. 1. Intern in a mental hospital. You'll always know exactly how sick someone is and everyone you're ever work with will seem easier. 2. Work with every population and every type of illness you can. You will find that there are some you work with more easily than others. There is your specialty. I specialize in Anxiety Disorders and Trauma so I see lots of people with panic attacks, phobias, excessive worry and control issues (because I work with them quickly) as well as traumatized combat veterans and rape and incest survivors (because I work with them painlessly).