As a mom, a researcher, and a writer, I’ve spent more than a decade diving into the science of happiness.

Along the way, I’ve collected what I call “Secrets of Adulthood” — the lessons I’ve learned, with time and experience, about how to create lives that are happier and more meaningful. Many of those insights come back to one of the most important roles we play: raising happy kids.

So I’m sharing 12 simple parenting rules I always live by.

If you have big plans for the day but your child isn’t cooperating, be willing to adjust your activities to suit your child’s needs in the moment. Sometimes I have to remind myself, “This is supposed to be fun.”

It’s no good visiting the zoo if my daughter is throwing one tantrum after another.