A psychotherapist should be professionally qualified. You can join courses offered by UKCP member organization. British Psychoanalytic Council (BPC), British Association of psychotherapists (BAP) and British Association of Counseling and Psychotherapy (BACP) also provide professional courses for psychotherapists. Honours degree in social work, psychology or similar qualification with relevant working experience vulnerable adults or kids is needed join these courses. You can specialize in various streams of psychology including analytical, behavioral and cognitive, experiential constructivist, humanistic and integrative, family, couple, sexual, systemic therapy, hypno-psychotherapy or psychoanalytic and psychodynamic psychotherapy. You can do part time post graduation once you start working as a psychotherapist extending for a period of four to six years. This will provide experience under supervision of senior therapists. a committed professional should be interested in new developments of psychotherapy. Ability to develop and maintain interpersonal relationships and accessibility with co workers to discuss professional as well as personal problems are essential for a successful psychotherapist.