Tension is what makes a book a hit with readers. Books that master tension often end up ranking high on bestseller lists. But few writers understand exactly what tension is or how to build it in their book.

Tension is a physical, emotional or psychological strain that your story presents. It’s usually presented through the plot. Tension causes readers to anticipate that there’s going to be a problem for the character.

They fear or feel for the character. Tension keeps readers living in a state of uncertainty. Will the character survive? Will the heroine ever find love? Will she ever get together with the hero? Will the detective figure out who the killer is before he becomes the next victim?

Using tension in your story is what creates edge of the seat, reading late into the night kind of books. It’s what makes readers blow off sleep just to read a few more pages. They read because they have to know that everything’s going to be okay for the character.

You use tension to make the reader ask questions in his mind and you keep the reader asking questions by raising the stakes – which in turn raises the tension. When your story first begins, your character has a purpose or a goal.

The reader knows this. You also present in the beginning what’s at stake if your character doesn’t fulfill his purpose or reach his goal. The beginning of the book is pretty calm – like being in a small boat in the middle of the ocean when it’s gentle.

Raising the stakes and raising the tension is when you have a big storm developing in the distance. The reader knows it’s coming but maybe the character doesn’t yet. So the reader is anxious for him. That’s tension.

The storm hits and though he struggles to keep the boat afloat, it capsizes and the character is tossed into the ocean. But he’s a good swimmer and he has on a life jacket. Plus, there’s a life raft he’s swimming toward.

If he gets in that life raft and gets rescued, all the tension is gone. But if, as he’s swimming toward the raft, a shark takes a bite out of it, the tension builds again. Then the character cuts himself on something so now there’s blood in the water.

That’s more tension because the reader knows what blood and sharks together mean. To keep tension building, you just keep raising the stakes. You allow the character to triumph over certain stakes but then you turn around and make it so that because he triumphed, that was the catalyst to something worse happening.

An example is a railway bridge that a train must cross has been compromised so the main character stops the train before it reaches that point. Hooray, he’s a hero! Only now, a mudslide is heading down the side of the mountain toward the train and it’s going to push it into the water below and make his problems more complex.

You do this no matter what the genre is. Keep readers wondering what’s going to happen next. Never write the obvious because readers get accustomed to that. If the guy in the ocean is rescued, let it come at a cost to him or to someone he loves.

Never end a chapter with everything smooth sailing. Create tension in your book, leaving the reader hanging at the end of every chapter except the final one where you tie it all together. You want them to reach the end of a chapter and think, “now what’s going to happen?”