Here's my "secret" recipe for happiness in life... Find something to do and someone to share it with.
Said another way, happiness in life hinges on productivity and relationship.
Productivity is meaningless without somebody to share your achievements with. Likewise, relationships can become trite and boring if you never do anything worth talking about.
I include all productive human activity under productivity. This is where you practice whatever you enjoy doing. Special emphasis on the word enjoy. Painting, writing, cycling, marketing, whatever.
I include humans, animals, and God under relationships. I believe you ought to have relationships with people you care about (of course!), as well as a strong relationship with God. Pets can be a source of additional relationship, although they cannot replace human interaction.
If you're looking for happiness and are stuck on complex theories about the so-called "meaning of life," stop it. When you boil it all down to the essentials, it's quite simple: something to do and somebody to share it with. That's it.