Outcomes before contents
A contents list written before the outcomes tends to mirror the syllabus you inherited. Starting from what the learner must be able to do produces a different and usually shorter book, and it makes each chapter testable.
Your Book Pro Book Coach
This route of Your Book Pro's Book Coach helps you turn what you teach into a book learners can use. It asks one question at a time about who the learner is, what they should be able to do by the end, the handful of concepts the book must make clear, and what people always misunderstand. It is free to talk to and you do not need an account.
A contents list written before the outcomes tends to mirror the syllabus you inherited. Starting from what the learner must be able to do produces a different and usually shorter book, and it makes each chapter testable.
The thing you explain three times every year is the most valuable material you have, because the existing books clearly do not explain it well enough. Those points often deserve a whole chapter each.
Exercises, worked examples and short scenarios are not appendices. In a teaching book they are the load-bearing structure, and deciding their form early affects how you write every chapter.
Regulations, standards and curricula change and differ by country. Books that state clearly which version and which jurisdiction they follow stay useful much longer, and Your Book Pro has a teaching mode that keeps standards and curriculum context in view as you work.
You already explain this material fluently in a classroom. Dictating that explanation and shaping it afterwards is usually much faster than composing textbook prose from scratch.
These are real Book Coach conversations, run with fictional starting ideas written for illustration. They are examples of how the conversation goes, not real authors and not real books. Expand any example to see the coach's first question, the directions it offered and a screenshot of the run.
The Book Coach is free, asks one question at a time, and does not need an account. You are only asked to create one if you want to turn what emerges into a working plan.