Martin Seligman, who has been mentioned above, also has a book "Authentic Happiness" which you might find interesting. As he points out, and you have experienced, inborn predisposition is the biggest factor in happiness.

However there are other big factors which you can partially control. You've probably already discovered some of them.

I think you would like the book because Seligman recognizes the fundamental difficulty of the problem. As you may have guessed, Seligman himself is predisposed to unhappiness.