If you're interested in reading more on this topic, here's a litterature list with some of the titles that have been great inspiration for me:

• "Positivity" by Barbara Fredrickson
• "Happy for no Reason" by Marci Shimoff
• "Happier" by Tal Ben-Shahar
• "An Invitation to Positive Psychology - Knowledge and tools for professionals" by Robert Biswas-Diener
• "The How of Happiness - A Practical Guide to Getting the Life You Want" by Sonja Lyubomirsky
• "Raising Happiness" by Christine Carter
• "Learned Optimism", "The Optimistic Child" and "Flourish" by Martin E.P. Seligman