One of the fastest ways to build authority for your brand is by writing a book.
A book gives you instant credibility in the business world. A book can be used in many ways, including: print, a PDF (Portable Document Format), or as a Kindle book.
You can use the book to make money but a better approach is to create the book for the Kindle format, create multiple calls to action within the text and give your book away for free.
This allows you to use your book as a lead generator to help you build your list, which should be your number one objective. Once you have a list of hungry customers who like and trust you, you can sell to them over and over again for years to come.
Millionaire author Gerry Robert created a book and used it as a lead generator. When I found it some years ago it was in a free PDF which I downloaded. I later discovered it was also available as a print version which you could buy, too.