Researchers have discovered no "one secret" to happiness. But they have found many different actions you can take, and each one will make you happier.
Find one that appeals to you and do it. You can become a little happier, and that will make a difference. Things will look a little brighter. You'll treat people a little better, which usually provokes them to respond in kind. You're a little more energetic so you get a little more done. Life is better all around.
A little happiness goes a long way.