Contrary to popular belief, I am not a millionaire. I know, shocking. Actually, most authors aren't. People tend tothink of authors on the level of J.K. Rowling or Stephen King-- really fucking well off. Truth is, most of us are broke, some of us are comfortable, and a few of us are rich.
We Independent authors tend to lean toward the broke or comfortable side. Most of us have day jobs to keep us in the comfortable zone. Because of this, we will take any and every sale and all the publicity we can get.
Yesterday someone with 13k+ followers retweeted a link to my book. An hour later I sold a book. Was the sale from that RT? I don't know, but it sure didn't hurt. Like I said, we'll take what we can get.
Another helpful thing for us little guys is reviews! Doesn't matter if you leave a master's thesis or a simple, 'Thumbs up. Good read.' Every review counts. When someone is on the fence about buying a product online, where's the first place they go? The reviews. The more the better-- even if they're varying in opinion. Those reviews are what will make the potential buyer commit or move on.
The final helpful thing is personal recommendations. You read this book. You loved it. Tell your friends. Tweet about it. Put it on the Facegrams and Instabooks, and that weird thing with the little ghost on the icon. Word of mouth is a powerful tool.
It costs you nothing and, believe me, we little guys appreciate it.