I'm back actively writing Book 4. I'm about a third into it and the action has started to build. That's good. But as I look back on the whole book so far, I'm realizing my hook is weak. That's bad.
As a rule, you want to have a strong hook to start your story so that the reader will become engaged and keep reading. For example, in Book 2, I start by showing Amanda's attempted abduction by the witch. Afterwards we learn that the witch has already abducted four other children. Since harming children is troubling to most, it works as a hook because we immediately want Evan and his companions to rescue these girls.
In Book 4, however, I have no such hook. The reader may be concerned about Iriel -- she recently had to choose between the mother that abandoned her and her friends. But I dispense with that in a few pages. Iriel is fine -- but not really. She is acting more human than elven. But I'm not sure that's enough to hook the reader. And there's no real action. Oh sure, each character has his or her own plot but that may not be enough either.
Of course, I'm talking about the fourth book in a series. So maybe I don't need a strong hook. Maybe the characters themselves are enough. But I don't think I'm going to rely on that. Time for some revision I think.