For obvious reasons, I go in search of writing and self-publishing tips all the time. I need all the help I can get, for starters, and it's always useful to see what others are writing about. What I've found is this: everyone seems to know exactly what it takes to be successful at self-publishing. They all know the big secret.
Big Book Sales
Yes, it's out there! The big secret to book sales...and it's everywhere. Buy this book, click that link, read this thing and you'll discover the secret. The trouble is, everyone has a different answer -- and often, a complex series of steps you need to follow to go with it.
But it really isn't a secret that to sell any product, you have to market it. And the very best form of marketing is, and always has been, word of mouth. So here's the real secret to selling books: getting someone who loves that book to talk about it. If you can do that, you're going to sell books.
First, you have to write a good book. Edit it thoroughly and check it for consistency. Get rid of anything you don't need. Next, put that book in a pretty package. Get a great cover and write an amazing blurb. Now, start giving it away for free.
Write to as many book bloggers as you can find (using a great pitch of course), and ask them to review your book. As the reviews start to come in (and you should be searching for them every day), start promoting them. Quote reviewers directly. Try interacting with them on Twitter to get them to talk about your book. Comment on their review. This refreshens the content, and that pings the search engines again.
It's not a secret: you need word of mouth to sell books. Even if you have to be the mouth and you have to give the words away for free, do it. This is the best way to get actual paying customers to read your words.