When I dreamed of being an author, I envisioned working at my computer and writing brilliant books. I never realized how much marketing and promotion was involved. These days, writers are expected to promote their books. It's in my contract.
Writing is a business, and marketing is a key part of that. The hard part is that it's often trial and error to see what works for you. I schedule my marketing campaigns, and then I track the analytics (e.g. sales numbers, blog hits, ad metrics, and costs) to see if there were positive results. Use your analytics on your website, blog, Facebook, and Twitter. There's a lot of good information there. I created a spreadsheet to track this information. I'll have details when I get ready to run the next campaign. Make sure all your hard work is paying off.
It feels weird to post about myself all the time. There are people who are uncomfortable with it. Try to balance your posts. The 80/20 rule is a good guideline. Twenty percent of your posts should be "buy my book." The others should be about other interesting things. Post recipes, pet pictures, hobbies, or other interesting things you do. And make sure you share others' content.
There needs to be a balance. Look at your newsfeed and see what your last twenty posts look like. When I'm cruising my Facebook newsfeed, I tend to hide or ignore the noise. I pay attention to sales (but not the ones that run every week). We have a furniture store here in Virginia that has a SALE!!!!! every week. The joke at my house is, "Oh, look. They're having another sale." I pay attention to contests too, but the "Hey, I got another 5 Star review" posts get mixed up in the noise of the newsfeed.
There are a lot of Facebook groups and sites to post your book information. Be careful if you do your posting all at the same time. People will see a string of the same post to different sites. Spread out or schedule your posts. I would also mix the content up too because a lot of readers visit the same sites too.
It also helps if you can find a group of writers to assist you. I'm in several groups for writers and bloggers, and we comment, post, and share each others' information. This helps get the word out without you having to do all the "Hey, look at me" posts.
It is definitely a challenge to get the word out and to keep your book in front of people. And sometimes, what works once, doesn't work a second time. Best wishes with your promotions. Drop me a note and let me know what works for you.