I was roaming around on the Highlights website recently, which sounds pretty strange unless you know that I was looking for the publication guidelines for writers, when I came across some helpful articles written by authors on writing tips. I really liked the two articles on creativity and action and adventure, posted below. If you're a children's book writer, check em' out, they may help you too!
Mary Lou Carney wrote an endearing article on creativity here.
And Dayton O. Hyde writes about action and adventure here.