It always helps to read what you've written. Last night I finished the final chapter of the XNA book. And then I read through it. And then I threw it away.
It was very worthy, concise and carefully written. It gave as good an explanation of component based development as you can get into 35 pages. But by gum it was boring.
So I've ditched it. Risking the wrath of my editor I've embarked on a rewrite to make it more interesting. Rather than class diagrams we are going to have "Hide the Controller", "Pell Mell Pelmanism", "Simon Says Party" and "Bread vs. Carrot".
I'll explain the code that makes the programs work, whilst giving people some very silly games to play.
Much more fun.