Just to be honest at the outset, I'm tackling a subject here that I don't know much about--the dreaded m word that every self-published author fears. I'm working on book seven now and have been hoping that sales will pick up because of so many books in the marketplace, but alas, I still have not found my tribe. This year I've spent more money on this, doing newspaper ads here in Tucson and paying for ads online. I've also found two or three places that for a nominal fee will tweet an ad for your book. http://masqueradecrew.blogspot.com/ is one of them. BooksGoSocial.com, a site based in Dublin, does reviews and features books for a nominal fee. Also has an awesome blog with many tips for writers.
A problem that I have which may not be your problem at all, is that I sign up on these sites, pay with paypal and then forget about them--apparently my mind has no follow-up ability. And following up is VERY important! (especially if money changes hands)
When posting on FB, blogging or tweeting, try and be consistent. By that I mean do it often, not do it the same. I've heard that posting early in the morning or late in the evening is the best time to reach readers. And don't just advertise yourself, try and expose who you are aside from being an author. And interact if you can with whatever subjects interest you.
I'm still struggling with Twitter when it comes to this. I guess it's the hashtag thingy that I find somewhat confusing. Maybe you can start a sort of thread by adding # whatever? and then see who responds...just putting a tweet out there doesn't seem to do much since I've posted questions that get no answers. For some reason I'm getting more and more followers and I'm not sure why. I'm muddling along with it and trying day by day to figure it out and respond in kind.
Facebook is an entire other world. I haven't been posting on my author page and have been told that I should. And according to my source, this should happen five to eight times a week! Doesn't always have to be about the books, in fact it's better if it isn't. (confusing, right?) I see people filling up the page with automatic posts. I do not want to do that no matter how entertaining they might be. If I personally do not have time to look something up and then post about it, forget it.
All in all be yourself.
Thank you for reading and I appreciate any and all comments!