Most o the books i've worked on have been well organized and well written already, may be even professionally edited. The main thing is that something isn't clear because something was left out or or not clearly connected to the other ideas. You introduce something one way, but you use it a different way. When there's code, a bugs in your code, not everybody runs their code. It's worse when they're using pseudo code, because then they can't run it. That's all i can think of.