I just read a blog entry from Gretchen Rubin on common happiness mistakes (http://www.happiness-project.com/happiness_project/2010/11/10-common-happiness-mistakes.html) and suggest that you read it as well.
In general, I can recommend to look around on her site. The web side is a resource full of interesting thoughts. Have a look at her “Happiness Project” book. It contains a structured approach to happiness! Further interesting reads are her secrets of adulthood (http://www.happiness-project.com/happiness_project/secrets-of-adulthood.html) or her twelve personal commandments (on the left side on the page)