Exposure is the best way to sell books, because if people can't find you they definitely can't buy. As a self-published author, you've probably got accounts on all those social media sites. You may already have a blog, even a website, to promote your writing and your books. But there's more you can start doing if you want to start getting exposure.
Blogging and staying active in social media, particularly book-centric sites like Goodreads, is a great way to get exposure for yourself as an author and by extension, your books. But you can always take things up to the next level, too.
First, you've got to identify what sort of author you are. If you write in a specific genre, you've got a good starting point. If you're a short story author, you're already ahead of the game.
Writing articles for magazines, professional blogs and literary journals is a great way to get exposure among a reading audience. But your stuff is only going to get published if it's really good, and it's only going to help you if you go about it in the right way.
Here's what you have to do: start thinking about topics that are relevant to your books and your writing. For example, I like to write mystery-romance books. I might write an article about real crimes involving couples who were once romantically linked. Maybe I'll call it Jilted: Real Crimes of Passion. Exciting, right?
That's the whole point. If you write about erotica, maybe you'll come up with an article about safe sex toys, or how to practice bondage in a safe way, or maybe how to find like-minded sexual partners. If you write children's books, an article about the important of youth literacy might be in order, or maybe something scholarly about how creativity is essential in child development.
If you're going to write articles, write them the right way. Use AP style and write in an engaging, informative tone. If you have a specific website in mind for your submission, read other articles on that site to get a feel for the tone they like. Cite your resources, cite your statistics, cite your quotes. Include an About the Author box! If readers can't find you, all this effort isn't doing any good. Offer your articles for free. They're more likely to get published if they're good and there are no strings attached, and the promotion you'll get in return is well worth the time and effort it takes to write the article. You don't need additional compensation.
Writing non-fiction articles just isn't for everyone, and even the most creative novelists struggle with simple newspaper copy. You can always write short stories, or submit your own short stories, instead. It's best if your short stories are in the same genre as the book you'd like to promote (because if readers like your stories, they're more likely to buy a book that's similar). Always include an About the Author box with the submission, and don't forget to include the contact information to help readers find you.