Derek Doepker is a bestselling author.  He didn't start out that way.  He had to learn what makes authors successful.  Now he writes and coaches other writers on what they can do for their own success.  He has cited 17 mistakes authors make that explain "Why Authors Fail."  He is a huge proponent of research as a tool to marketing success and recommends the ASPIRE method as the key ways to promote your work that will yield the results you'd love.