Every author should be at the very least on Facebook and Twitter . Social media is where the majority of readers get their information on authors, new releases, books on sale and reviews. There are specific Facebook Groups that are dedicated to simply promoting author’s books.
If you have a personal Facebook account then you can set up an author page. It’s very simple to do. Once it’s set up, you can post about your book being on sale, or it’s release date or your next book signing.
Don’t forget you can hold events on Facebook too. I was fortunate to be a part of one of my author’s Romance Writers Gone Wild event in November this year. It was amazing! So many authors volunteered their time and a few bucks for the overall prizes and to share books excerpts, interesting facts, reveal covers, announce new books and lots of other fun! There were over 600 Facebook attendees. You might want to look into doing something similar or just having your own Facebook Event.
GoodReads is a great place to get reviews as well as place a few ads or hold a giveaway.