Here is an article on the Grant Study at Harvard on Happiness.
This is seminal work in the field.
My book "The Business of Happiness" deals with many of these issues, and we focused on the following:
- Being an active participant in multiple communities of interest
- Showing gratitude by giving back
- Having high levels of self expression
- Developing high levels of empathy
- Pursuing a higher calling
- Developing double bottom line lives and businesses
Just because you are successful doesn't mean you will be happy; but if you are happy you can no doubt become successful.