Creating a proposal is simply a tool for thinking about your book project in a clear and thorough way. Write a proposal even if you self-publish.
There are many useful guides to writing book proposals. Michael Larsen’s How to Write a Book Proposal is iconic. Michael Hyatt’s guides are shorter, useful, and popular. Write the Perfect Book Proposal by Jeff Herman includes sample proposals. This post by Nancy Peske is also useful. And these instructions from Jane Friedman are not to be missed.
You can find many other resources with an Internet search.
I’ve been using the following checklist to keep things simple and remind myself of a proposal’s core elements. (It applies to non-narrative, nonfiction books.)
Title. Choose one that states your book’s premise or promise in a brief, vivid way. Use a subtitle if it helps.
Premise. Summarize the main problem that you will describe in your book and the core solution that you will offer.
Promise. Briefly describe your book’s main benefits and features: Readers will be able to [insert benefits here] because the book will [insert features here].
Overview. Briefly describe what the major sections of your book will include—the problem, solution, and recommended plan of action, implications, or applications.
Manuscript. Describe how much you’ve already written, the projected total word count, the projected date of the finished manuscript, and any visuals and special features that you intend to include in your book.
Audience. Describe readers in terms of their demographics and psychographics (their attitudes, desires, and behaviors as they relate to the topic of your book).
Competition. Describe existing print books, ebooks, websites, and apps on your topic. State what your book will offer that they don’t.
Qualifications. Describe your education, training, experience, previous writing, and current online presence (including numbers wherever possible).
Platform. Describe how you will promote your book—for example, by speaking, consulting, appearing on radio or television, writing articles, or expanding your online presence (including audio, video, email newsletters, webinars, and online courses).
Vision. Describe any future books and related products, services, or events that you plan to develop.
Synopsis. Write an annotated table of contents for your book—headings and subheadings expressed as complete sentences wherever possible. Add brief descriptions of the supporting material that you will include (facts, stories, studies, quotes).
Sample chapters. Write one or two chapters—4,000 to 8,000 words each—to show that you can deliver on your annotated table of contents.