Read everything you can on the subject. Whether you are writing a nonfiction book about life experiences, a process, project or diets and health, you will need to have a firm grasp on the subject and how you are going to write and structure the book. Non-fiction requires accuracy, validity and as much information as you can get your hands on.
Take copious notes and do an abundance of research in the beginning. You can build on your research as the book comes together, but you should always do more research than you think is necessary beforehand. Research is the biggest piece of the puzzle and should take up most of your time when you write a nonfiction book. It helps to tape record your ideas as they come to you, or write them down in a journal you keep with you at all times. Don't forget your bibliography when submitting your book to agents and publishers.
Organize your research. With any online sources you find, it may be best to make a hard copy, as well as keep a folder on your computer's hard drive. Having hard copies and multiple electronic sources with all of your information saved can keep you from the hassles of failing hard drives and lost documents when you write a non-fiction book.
Use examples from fiction writers and even listen to their advice, to write a non-fiction book. Use dialogue and tips from figurative speech to suspense to help you have fun while writing and help engage your readers.
Break up the project into manageable chunks. Take the subject chapter by chapter. This will help you write a non-fiction book without being overwhelmed by the process. With a passion for writing and taking one portion at a time, you can perfect and tweak as you go along and end up with a wonderful manuscript.
Begin with an anecdote that draws the reader in, and then close the book the same way. Throughout the non-fiction book you can also use the theme of the beginning and end as a through line to connect all of the dots you have created with your research. Using this book end method can really help your story flow, like a fiction novel or story.
Set goals each day for writing the nonfiction book, in order to keep yourself on track. Use the research you have done to help you organize the chapters and sections of your book. You can begin with one school of thought, and then present the opposing views. Or, you can present a string of opposing views and talk about each view in a separate chapter.
Talk to every writer you can find to get a clear picture of how to write on your particular subject. As you are talking to experts and professionals in the field, take down lots of quotes to pepper your non-fiction book with in order to liven up the writing and reading experience.
Make the time to write and devote large amounts of time to writing. Even with the busiest life-style, there are ways to make time for the important projects you wish to finish. Even if it means going to bed an hour later, or waking up an hour earlier every day. You must carve out a niche of time each day to work on your nonfiction book.
Step away from your nonfiction book after you have gotten a solid first draft finished. You must get some distance from the subject and the book itself before you can look at it with fresh eyes to do extensive revising.
Revise the first draft after a few weeks or months have gone by. Depending on the size of your book, you should devote an extensive amount of time to each portion of the book, and add and subtract as you see fit. Your goal is to remove extraneous material and leave only what the reader needs in order to follow your line of thought on the subject.