Every scene in a story should play a part in moving the story forward--with purpose. Just as dumping a ton of back story into your first chapter is not the best thing to do, any scene that hasn't been planned out may fail your main character and thus...your story plot and ultimately your readers.
So, as you are writing your story, whether or not your plot or pance, you should be asking yourself a few questions about each scene. The first question to ask is:
Is this scene necessary? What purpose does it serve?
If you cannot answer those questions, are you sure you have a scene that is important to the plot of the story as well as the character arc of your main character? (Hero/Heroine)
Each scene should show your character's wants or needs early on so it is clear to the reader. So, what is it the character wants, and what happens in this scene to show that to the reader? Put your character in the scene or a normal day, normal things, and what happens to change up where this character was headed? What has caused the problem or what stands in the way of the character getting what they want or need and....why? In other words, toss in CONFLICT!!! Throw in a roadblock that changes what the character thinks is going on or something that makes the character now have to make a decision.
How do you reveal the conflict in a scene--without giving the full plot of things away?
What is it that happens to toss the character right into the middle of a mess? Toss in the strange, weird or unusual....why not? Your character is having a normal day so how do you make the scene take the character on a turn for the worse. Many authors will tell you to put your characters through hell, it makes for a better story. Once you iron out what will happen to change things up, then go back and look at the emotional arc of your character.
How does the character react to the conflict or problem...but more than that how does it affect them internally and externally. It may help to write these things out as you are thinking through a scene. How does your character respond? Think of all the senses in what your character encounters. What do they see, hear, smell, taste, and feel physically? What happens to them emotionally, even if minimal. Emotion can be the first reaction to how a character is motivated or will decide what to do about the conflict. Spell out what are the characters' motivations and how this scene adds to the overall plot in the long run.
How does this scene get your character to his/her overall goal? It might help to start jotting down all the plot points along the way as they occur. If you are a panster, then this part can be done once you have the first draft and are working back through the story a second time. When I am writing I call if fluffing--adding more word count, but word count that does count. Words that add to the tension and make the reader what to turn the page.
What happens due to this scene? Does this cause your character to win, lose or plan around the conflict in the scene? Think of the conflict as an obstacle---did it trip the character up? How? Now, what?--or is that where you turn the page to the next chapter leaving a cliffhanger? It better be something good!
But as you are writing, think about the possible outcomes related to the conflict in the scene and your character's reaction. Does this scene leave you on the edge of your seat as a writer/author? If not majorly, then you need to increase the tension with a rewrite and more collateral fall out---damage so to speak. Add more conflict and make the stakes higher. Create a cliffhanger due to the conflict that tossed the character right out of their normal and into the fire.
Planning your scenes with the specifics of placement of conflict will stir up a story readers cannot put down. A bit of planning will keep the tension up in any story but also keep you on track not to go off on a tangent while you create havoc for your characters.
All writers will scold themselves about a saggy middle of a story that just isn't happening. This is not writer's block, it's simply a lack of planning and even if you are a panster like me--there is still a certain amount of planning that has to happen. Go back to the last big conflict and keep reading forward and think about what can be tossed in to create more conflict and more difficulties for your character that also makes sense to the central plot and the characters' motivations. Toss in the unexpected that just devastates your character's plans or motivations. Seriously! It sounds like a bad idea, but really it's not, it will keep your reader engaged!
Create conflict enough to put pressure on the hero/heroine that compels them to act, which drives the story forward. Do something that causes your character to have to make a hard decision that might stop them from meeting their goals. Send them to a place where they have no idea what to do.
Authors who write suspense will say, kill someone or burn something important down when you hit the saggy middle of your story. That will cause your character conflict and decisions to make the story engaging. It's true sometimes characters don't always follow what we have plotted out, so also give your character permission to act or respond how that character decides. I know sometimes my characters have written parts of their own stories and when that happens it is magical. Character-driven stories are the best when it comes down to it, so while you want to stick to your main plot, give the hero/heroine some freedom to react and make decisions that fit them and boost what is happening.
So let's go back to the conflict. What happened and now what is your character going to do? Make the choices or lack of choices difficult. Don't make things easy for your character.
I have used Scene & Sequel by Dwight Swain to get a grip on what is really happening with the conflict in my story.
1) Goal-Make sure the character's goals are mentioned in the first paragraph of a scene but maybe subtle hints. This is a scene goal, not a full story plot. This gives the reader a question to ponder about the character or the characters' thoughts or something that comes out of the dialogue.
2) Conflict-What are three things that can bring conflict to that goal within the scene? Show three exchanges of push or pull action or dialogue causing conflict. Think of those three items as stimuli and responses.
3) Disaster-How does this end for the character in this scene? How did things worsen based on the character's response? How does this make things harder for the character and his/her goals?
The big question: Did your character achieve their goal for that scene or not?
A couple of things could happen depending on your character's response:
*Yes, but...now there are consequences for what the character did.
*No, the character hits a dead end and has to plan something else.
*No, and now things are way worse for the character.
Once you figure these out then what needs to happen is the following three items:
1) Reaction: What emotions does the character go through and what are his/her thoughts. Give some physical reactions along with the thoughts and emotions.
2) Dilemma: Give the character thoughts on what the heck are they gonna do now. Don't give the character a ton of choices, make this hard and narrow down the choices.
3) Decision: What is the new plan and where is the character headed now? Send your character down that new path of dealing with the crisis.
If you can answer these questions and think through each of your scenes with the items mentioned you will raise the stakes for your characters and engage readers to the point they will turn the next page and keep reading. Whether you are a heavy-duty plotter or a total panster, asking some of these questions will give you a better-balanced story. Each chapter or scene will move the story forward and keep your readers engaged.