If you are reading this blog post when 'Bridge to Terabithia' is still playing in the cinema, and you haven't seen it, may I make a suggestion?
Move AWAY from the computer. Get your purse/jacket/wallet and head out to see it. Right now.
This is the best children's movie I've seen for years and not only made me cry but is beautifully adapted for the screen, and captures perfectly what it is like to be a child who lives in a make-believe world. It wasn't just the storyline that made me cry, it was being reminded so sharply of what it feels like, as a child, to lead a younger sibling into a magical world you've created just for them.
Ah, but you're writing children's books now, you may say. You'll be doing that for your readers.
It isn't the same. Writing is hard, technical work. But as a kid I once led my baby brother into an old, overgrown and walled orchard at sunset and convinced him that the apples were enchanted, that we had to cross the orchard without looking back ONCE. I swear...as we crept across, my brother trembling with excitement, in the corner of my eye I saw those trees move.