In writing about creating credibility with a book, I realized I have TWO standards to go by based on experience, and a caveat.
First, the caveat: A book created for credibility without taking at least a minimum of best practices into account can BACKFIRE, or actually cost you credibility. There are pretty good and painfully amusing examples. When I explain what I consider a “healthy book” just consider those elements NOT being present in the “unhealthy” one, and you’ll understand.