Writing your novel or nonfiction book is only the beginning. If you want people to buy your book, you need to develop an author platform as part of your marketing efforts and to build a relationship with your readers.
Speaking to the Indie Publishing Austin meetup, Tom Corson-Knowles (the bestselling self-published author of 20+ books including The Kindle Publishing Bible series, founder of TCK Publishing, and host of The Publishing Profits Podcast), offered up excellent tips on how authors can build an online presence and an audience for their books.
As he defined it, the author platform is the combination of methods, tools, and resources that an author uses to connect to readers and build an audience.