I think that happiness is contagious. The more you surround yourself with happy people, the more happy you become. It is as easy as that.
You know how you can have the crappiest day ever and then hang out with your happy-go-lucky, giggly, 4 year old and all of a sudden, you are laughing and in a great mood? Or when you are feeling down in the dumps and play with a puppy? You just can’t help but be happy, right? Do you have a friend that always seems to look on the bright side of things? Or is always in a good mood? The friends that rarely ever complains? Hang out with her more often. It rubs off.
Take a look at what the happy people in your life do. How do they act? What do they talk about? How do they spend their free time? What does their day look like? What is their body language saying? How is their posture?
How can you take some of their traits and actions and add them into your own life?