(Source: Sonja Lyubomirsky, The How of Happiness: A Scientific Approach to Getting the Life You Want (2008), pp. 88-254.)

1.  Take time to express gratitude, either by writing or talking to another person or through personal reflection.  Do this at least once a week.
2.  Cultivate optimism by imagining where you want your life to be a year or a decade from now.
3.  Avoid excessive rumination by not comparing your life to others.
4.  Practice a variety of acts of kindness on a weekly basis.
5.  Develop a strong network of social support by expressing admiration, appreciation, and affection for others.
6.  Develop strategies for coping with the stresses that life inevitably brings.
7.  Forgive those that do you wrong and move on.
8.  Absorb yourself in more "flow activities" (those challenging activities during which "time flies")
9.  Identify those small things that bring you pleasure and savor them.
10.  Reminisce with family and friends about good times together.
11.  Be mindful of the here and now and take pleasure in sensory experiences.
12.  Strike a balance between thoughts of the past (nostalgia), anticipation of the future, and experiencing the present.
13.  Set goals for yourself that are consistent with your deepest values.
14.  If you can, develop a spiritual life.
15.  Learn and use meditation techniques.
16.  Exercise.
17.  Get adequate (but not too much) sleep.
18.  Act like a happy person.
19.  Add variety when you implement the strategies above.