These simple tips will help you culticate gratitude in your daily life. By Catherine Price Reprinted from Greater Good Magazine, Vol. IV, Issue 1. Used with permission. Research in positive psychology has identified several ways that practicing gratitude can boost people's health and happiness. Here are four of these research-tested "gratitude interventions." Write a gratitude letter. Research by Martin Seligman, Christopher Peterson and others has shown this one to be particularly effective. write a letter to a mentor, family member or someone other important person in your life whom you've never properly thanked. Deliver it in person and read it out loud. Keep a gratitude letter. Studies by psychologist Michael McCullough, Robert Emmons, Sonja Lyumbomirsky, and others have backed up this exercise, which involves keeping a list of things for which you're grateful- anything from your children or spouse to the beauty of the tree outside your window. Doin...