These "SECRETS" actually work for everything from Breathing to Cleaning your toilet, to Brain surgery, but it's always good to remind ourselves not only WHY we do things, but that it's really not that HARD to make our efforts WORK OUT.
Here we go.
Everything basically boils down to SO WHAT, WHO FOR, and ENGAGE!
All of these things are connected, too, and I'll show you how it works.
This is a question I generally ask most of my clients and pretty much everyone who asks me for a review. If I don't physically ask the person making the request, I certainly ask myself, trying not to use my snarky voice. So what? What's the point? Why should I read this book? More importantly for authors, why should I write this book? What am I trying to do? Writing is done for two very, very basic reasons--to inform or to entertain, both very worthy causes and nothing wrong with either. Those who NEED to be informed by something I have to offer in a way that no one else can convey expect me to not waste their time; likewise, those who WANT to be entertained in a way that only I can provide do not want to feel cheated. My point as an author in writing non-fiction or fiction is to write for the one person who buys my book because he or she is drawn in by my subject. Either my backdrop theme is so universal, say World War Two, that it may appeal to an international audience of both men and women no matter how technical or graphic or tightly focused the subject (like a story about cooks or procuring food for the soldiers or starving occupied), or my subject is so compact, maybe dealing with clay soil in my garden, that it appeals to a niche market.
When I am working on a book, I need to keep a visual reminder at hand to keep me directed/focused on the point or theme of my book.
As an author, it's my duty to know what I'm writing, and consider the impact it will have on the audience...which leads us to...
Within the two types of readers vs. non-readers there are subsets, but basically readers fall into two categories: those who GOBBLE books and those who DIGEST books. Book gobblers are usually people who download everything to their ereaders and read it, delete it, move on. They may be a group of ladies who buy subscriptions in book clubs and pass around the little books, marking their initials in them to remember which ones they read. They may be romance junkies who or mystery readers who get books from the library, read, and return. They read just because and maybe develop affinities for certain authors or genres, but they don't leave reviews and maybe tell their immediate buddies what they're reading, but that's it. They are a great audience and that's fine. That's commercial fiction. Then there are the readers who buy and maybe collect books, whether new or used, they keep those books and read the latest "best sellers" and probably belong to reading discussion groups. Digesting readers like juicy subjects and voice their opinions. They may be reading the commercial fiction of some of the biggest sellers, or it may be popular memoirs, biographies, controversies, or policy or some sort of help-help or study book, but they are deliberate about their choices, whether through recommendation or through considerate browsing.
Can I cross-pollinate my audience as an author? Sure, but don't try to sell a romance to a true crime fan. Once you start blending, readers squawk and your novels or self-help book becomes either a mess or its own tiny sub-genre. (Seriously, read the book industry study group's category list.) I recently responded to a question from a small publisher about how important sub-genre is--and I was the only one who responded that it is important for writers to understand what they're writing and stay within expectations to a point. Book gobblers only like a mild "aha"; other readers like subjects that resonate to them personally, and are definable by relating to how bad or how good either the topic or the main characters are. Which leads me to...
Authors want to be read...right? The more we get folks talking about our books, passing it around, sharing, the more we hope people will buy our books. Funny that even when readers share books, sales tend to rise as people who like something turn around a buy a copy either for themselves or as a gift. The way we get folks talking is by engaging them in our theme/subject/characters. What books do you like to read, and why? Make a list, and quickly--without too much thought--write a sentence or fragment about the first thing you think of when you thought of the title, a scene that stands out, or what the book was about. If you're a voracious reader, there are going to be some that leave a permanent mark and others you have no memory of even opening. If you're an author who has more than a dozen reviews, chances are some will be poor and some off the top adoring. Some people "get" your point; others never will. Authors cannot please everyone, yet we will please many readers if we allow them to participate in the experience of our fictional characters by bringing them into the story and not reporting the action like a journalist or recording the dialog like a physics lecture. Have someone read back your dialog. Is it natural? Our non-fiction is well-defined by presenting a problem and solving it. Who NEEDS to know about grandma's philosophy on raising kids these days? Chances are, it's going to be a pretty niche audience unless there's something utterly unique about the setting and the results.
Can your reader feel the emotion or the setting? I had a contest judge say he felt cold while reading my scene. The more reaction you can tug with both hands from the reader, the more intense the response and the desire to share the experience.
Just like life--we breathe to live, we clean our houses to provide a healthy environment, we allow/perform brain surgery to fix something that will allow us to function better--Authors who can make universal points in well-known backgrounds (The Book Thief, Lord of the Rings), who write for specific but large-reaching audiences (Jodi Picoult, Tom Clancy) and can engage the reader no matter the theme (Laura Hillenbrand's Unbroken, Erik Larsen's Dead Wake) (and have friends in high places) will do the best market-wise. The rest of us will either have fun or...not.