Raising Happiness: 10 Simple Steps for More Joyful Kids and Happier Parents by Christine Carter, Ph.D.
I would place this book on my "Must Read" shelf for good parenting. The author is the director of the Greater Good Science Center at UC Berkeley, and also has a blog:
If you have read a lot of books about positive psychology or about intentional parenting, this book won't tell you anything new. But what Carter has done here is to collect and boil down the research and the Best Practices that studies have pointed to, and laid them out as 10 Simple Steps you can work on to increase the happiness levels in your home.
1. Put on Your Own Oxygen Mask First (and fix your marriage if you have one)
2. Build a Village (who are the people that are out there to support you and your kids?)
3. Expect Effort and Enjoyment, Not Perfection (freeing yourself from perfectionism)
4. Choose Gratitude, Forgiveness, and Optimism
5. Raise Their Emotional Intelligence
6. Form Happiness Habits
7. Teach Self-Discipline
8. Enjoy the Present Moment
9. Rig Their Environment for Happiness
10. Eat Dinner Together
Carter describes the research, and also describes her own experiences with her two daughters. Carter isn't perfect - she's divorced, she's made mistakes, she's pretty humble - and that actually makes the discussion much more accessible.
It's never too late to change a few parenting habits for the better. This book is a good place to start that.