How's your NANOWRIMO going?
One thing a lot of writers run into trouble with is how to create TENSION on every page, especially in the middle of the book. Here are a few quick tips.
1. Give your characters strong OPPONENTS. In the middle of the book add a new lesser ANTAGONIST if your main antagonist isn't in the picture. Make sure the new antagonist challenges the protagonist in ways that move the story forward and carry the protagonist farther along the trajectory of their arc. Torture your protagonist!
2. Give your characters strong WANTS. I know I keep saying this, but it really works. In the middle of the book your character may have already achieved his/her initial want. Give him/her a new, escalated want.
3. Use SETTING for conflict, either directly (a haunted mansion, a dangerous precipice, a storm) or for contrast (a bucolic setting where people are arguing)
4. A FLASHBACK to a trauma from a character's past can add tension if the present time action is slower. Try to write these as scenes, not exposition.
5. FORESHADOWING can be done with ominous description. If you are using omniscient POV (Death, God, an Angel, a disembodied all-knowing Presence etc.) or first person with a character who already knows what is going to happen, the ominiscient voice or at least partially informed first person narrator should be too savvy to give everything away but smart enough to drop hints that will keep us reading. If you are using close third or first in present tense or told from a character who is looking back only a short ways, they won't be able to foreshadow things but you as the author can!