I think it's important to have a good hard failure when you're young... I learned a lot from that. Because it makes you kind of aware of what can happen to you. Because of it, I've never had any fear in my whole life when we've been near collapse and so on. I've never been afraid.
By used books. They have the same words as the new ones. Also libraries.
The most important thing is to be willing to question everything.
The child is not a passive recipient of knowledge but an active participant in the learning process.