The thing is, middles are insanely tough to write. Which is why for the first few years of my career, I wrote lots and lots of beginnings. Part of the problem is poorly fleshed out ideas, and this happens as a professional writer as well.
When my friend, Roseanna, and I talk about initial story ideas, we usually have a set up in mind. Like, “Girl crashes on deserted island with two other families.” And then we follow this up with, “Drama ensues.” (Or often, “romance ensues.”) This right here is a recipe for what we call a “sagging middle.”
The first thing you should ask yourself is, “does my main character have a goal?”
People, GIVE YOUR MAIN CHARACTER A GOAL. He or she needs something compelling him through the story, and the surest way to fix a sagging middle is to give your character something to work toward. Because you know what you do then? You throw complications at them.
Say your character wants to be a private investigator and is trying to prove she’s just as tough as the male P.I.s. What kind of complications can you think of? Maybe she’s forced to go into a situation that involves a lot of spiders and she absolutely hates spiders. Maybe she has to partner up with a total chauvinist to get the job done. And toward the end of all this, maybe she’s in a hostage situation and questions if this really is the right line of work for a woman to be in. (That last one would be known as the character’s “darkest moment,” which comes toward the end of the book. More on that later.)
These complications are what carry your book through to a stellar ending. So if you’re having trouble with your middle, the first thing to do is ask yourself if your character has a goal. If so, brainstorm ways to keep them from achieving their goal and voila! A much improved middle.