I am happy to find the book The How of Happiness from our library. A very powerful science book. Using the author Sonja Lyubomirsky’s words,
… the first ‘how-to-become-happier’ book authored by someone who has actually conducted research revealing how people can achieve a greater sense of happiness in their lives.
The following quote is from an article by the same author. It confirms that we can change our intentional activities towards become happier. See Layous, K., & Lyubomirsky, S. (in press). The how, who, what, when, and why of happiness: Mechanisms underlying the success of positive interventions. In J. Gruber & J. Moscowitz (Eds.), The light and dark side of positive emotions. New York: Oxford University Press.
The last decade of research has not only established that happiness can be increased through intentional activity, but has begun to parse the details of the how, who, what, when, and why of this important process.
Also, a lecture given by Dr. Sonja Lyubomirsky is on YouTube.