What's the 'it' ? It's the message you want to deliver. It's what you've discovered yourself that you want to share through your book. Ideally, it ties back to a theme in the title (or subtitle). It's not about you -- but you can be the vehicle to deliver the message -- to inspire action, empower and provide practical knowledge others can benefit from. Your already an expert, and as an expert you have a desire to share the message and show others the way to 'it'.
State the problem.
Explain how the world is changing & evolving -- excite a rally and invite them to get involved -- have an opinion one way or another (try to stay off the fence).
Discuss the opportunity & benefits for the reader.
Your quick story/back story & how it benefited you personally (make it real to the reader).
How it will benefit them (the reader).
That it's possible & easy & doable -- break it down for them in 5-10 steps.
Explain that you'll show them the path through the rest of the book.
Quick summary of What's to come (in the chapters that follow).
Chapter 1: The opportunity & my story -- Your positioning as an expert
Current state of the industry or field or endeavor.
How things have been changing.
Make the case that a new approach is needed.
Those that don't know this new truth will be left behind.
How I figured it all out.
Chapter 2: The big solution framework (ie. 7 habits)
Chapter 3-10: Breaks down the big solution into separate components (1 idea per chapter)
Chapter 11: The big obstacles the reader will face
What's the #1 thing that will prevent them from taking action & succeeding?
How will they overcome it? (How did you?)
Chapter 12: Conclusion: The marching orders -- putting everything in action, taking the next step. You might invite readers to share their own stories through your website.
Remember: Your book is a vehicle to get the message out. You as the author are the messenger for a message larger than yourself.
Please feel free to share this and my only request is attribution (with a link back to my website, selfpublish.org).