You want to write a nonfiction book--perhaps a how to book or a self-improvement or a book of essays.
If you're an online writer, then consider writing an article series.
An article series are self-contained articles that can be used as the chapters of your nonfiction book.
First, you should not sign away the copyright to these articles, but should publish them in non-exclusive format.
Write the title of your nonfiction work. Write an outline of the chapters. Perhaps you decide your book should be 12-24 chapters.
Once you write your outline, then you can begin writing the articles for your selected websites.
You can publish the articles with one or several web content provides.
Again, these should be self-contained articles.
For example your nonfiction book could be about sales and marketing strategies.
Each chapter then would focus on sales and marketing strategies, e.g. for online marketing.
You have your title, you have your focus of the article series.
Then you can begin your research.
What are the principle marketing strategies used in e-commerce?
If you're an online entrepreneur, then you should already have most of the information. The research is filling in the details and providing example from online entrepreneurs.
In addition, perhaps others are making use of marketing strategies that you haven't yet made use or don't yet know about, some of these perhaps new and innovative.
Each chapter or rather each article focusses on the traditional online marketing strategies and then the innovative techniques.
You write the article series and publish online.
Once you've written your series of articles then you have your book.
You can submit this book to a commercial publishers and/or you can self-publish with a print-on-demand publisher. Or you can self-publish first and then submit to a commercial publisher.
This technique can be used to write other nonfiction works.