First, I want to be clear that I’m referring to the characters in your book, not you. As writers, we encounter enough tension without ratcheting it up any more.
I attended an excellent workshop on this topic given by Donald Maass at a Pikes Peak Writers Conference a couple of years ago. I loved it, listened to every word, took notes. Yet it’s amazing how you can know you need to do something, but still not do it. My wonderful critique group recently reviewed my new middle grade novel and suggested that my middle sags. My defensive hairs rose and I told them I’d been trying to exercise. They clarified that they were referring to my story.
When I went back and reread it, I had to agree. Sometimes in writing, there’s a tendency to let events happen while you’re making your way from a turning point to the climax, and that’s what I’d done. I’d let my character wander through life, letting things happen to her when I needed to give her a purpose and make her drive the events. And I needed the purpose to be so important and the obstacles so imposing as to take her out of her comfort zone, i.e., ratchet up her tension. What I found as I dove into it, was that I already had all the storylines set up to give her the perfect purpose during this otherwise sagging middle—a purpose that sets the stage for great tension. All I needed to do was create it. Why hadn’t I seen it from the beginning? Thank goodness for critique groups!
As the tension escalates, so do your characters’ responses, to the point that they do things that are actually “out of character.” I find these scenes fun to write, but challenging. Obstacles can be overdone to the point of unbelievable, as can the character’s responses. But the challenge is worth it, because there’s nothing worse than a sagging middle!