If you've ever considered writing a book, you know there are a lot of posts out there that can help you with the mechanics of writing. However, I find many don't address the essence of it. I write thrillers that breathe and have a heartbeat because I flesh-out my made up world on the bones of the real world. That makes it easier for my readers to accept my lies, but it makes it harder on me because my lies have to ring true.
1. Know Your Stuff
Unless you're writing a non-fiction book about a specific event in history, you're going to be able to take some literary license in your subject matter. That's truly the gift and the curse in writing a fiction book. You can do whatever you damned well please. It's your thoughts, it's your world. So create what you want. That's the gift part, but for your work to be truly believable and really give the reader a great experience, you're going to have to do a lot of research and know your subject matter inside and out. That's the curse part. In order to create a believable world with problems that hook your reader into your drama, you have to be able to draw clear and concise pictures with only the words you put on the paper.
That's where knowing your stuff comes in. My training as a lawyer drilled into me the power of the crafted sentence and the hidden power of manipulation in the omission. If your story has a backdrop of a specific event, then know the event, the time of year it happened, news analysis of all perspectives, who the major players were, etc. This is not to say you have to memorize and quote all sorts of details, but you want to know at least as much as your least informed reader and you should know a bit more than your better informed readers. That way, you can still create your compelling tale and it will be seeded with enough details that: 1) you're educating your lesser informed readers and 2) you've earned the trust of the more informed readers so they'll be willing to stretch their "belief bubble" to keep reading your entertaining story.
2. Know When to Bluff
Knowing your stuff does not mean you have to become a big bore. Different authors and different audiences will have varying degrees of need for explicit details. If you're writing a tale about military procedures in the Arctic, then you had better be aware of the effect of extreme cold on rifles and whether it's likely your characters would use Gun Butter or not. (I'll let you google this question for yourself.) Some readers love the minute details and others simply want to know enough move on with the story. Just because you know all the answers from googling Gun Butter does not mean you have to write each and every fact down. You need to know enough about your subject to know what you don't know to avoid tripping over a fact that causes your readers to lose trust in you. However, what you choose to put on the page is as important as what you leave off of it.
The power of the omission is a huge and wonderful device. An omission is leaving out a fact or a reaction that your reader could have wanted or needed. It can be used for pure bluffing purposes - when we truly don't know the answer in spite of our research - or for pure manipulation - when we need a bit more time to weave our tale. Also, the magnificent omission is when you know your reader will assume something - like a character's innocence - and you let them believe it because that assumption helps your story grow.
3. Know enough to stretch the "Belief Bubble"
Writing a good thriller means expanding your reader's world a little bit at a time. Your reader lives in something I call the "Belief Bubble" - simply it's a little bit of space surrounding them that keeps the real world out and let's the story expand on the breath of your lies. If you've done your homework on setting, character traits, skills needed for character development or story texture and much more, you are well on your way to creating a great reading experience because you can expand the reader's bubble a little puff at a time. Readers will let you do this for as long as they are engaged in your story. If your story takes an off-the-wall turn or the facts don't line up just right or your character's motivation doesn't ring true, you run the risk of bursting their bubble and they won't read another word.
A good, heart-thumping thriller is based on what the reader knows or thinks they do. The essence of your story exists in the details - both stated and assumed. Your job is to mesh their world with your made up one.