Step wise, I'm sure you know about Stepmonster (on the side bar).
When it come to teaching kids/child development, I love Vygotsky. It's everywhere in all of my posts. He's the one that focuses on giving your kids the gift of confidence to help them learn and grow. If you're not yet set on a child development theorist, you can pick up a book like this for an introduction. If you have more of an idea of what you're looking for I'm happy to search deeper for you to help you find the right fit.