Much like in self-awareness, people researching this field also often get confused with similar naming. Positive psychology differs from The Law of Attraction and Positive Thinking - although it is in some way tightly tied to.
In a search for a more satisfactory life, a new branch of psychology in general has emerged, positive psychology is intended to help one lead a healthy, happy life. Even though psychology in general mostly revolves around atypical and bizarre behavior and dysfunction, positive psychology is more centered on the pure value and promotion of happiness.
In fact - positive psychology is the study of happiness it self, in order for one to become more happier and lead a more fulfilled way of life.