A subplot is a mini plot. These types of plot can enhance the premier plot of your story by breaking the action up. Nothing enhances tension like a suspenseful cliffhanger or a series of cliffhangers. To weave subplots into your story doesn’t mean you can skimp on anything in the first plot. The tool I use the most is beat sheets, which I use on my top level plot and any and all subplots. In short, I plan them.
After completing a beat sheet for the plot story I want to tell and all subplots, I take the beat sheets and put them beside one another. A side-by-side view helps me determine where each beat should go in a combined sort of beat sheet. This method is how I control the pacing of each plot.
A subplot should complement the leading plot. A subplot can be blocks of text dropped in to break the action. They can run in tandem with the action. Each kind of subplot serves to add layers to the story. A subplot can break up the action, as mentioned before, but they can also push the story forward. In some instances, a well written subplot can help in characterization by showing motivations, as well as aspects of the character’s personality.
Ask questions of your subplots. Questions like, “What is the goal of the character starring in the subplot,” or “How does it affect the story?” Remember you can take the subplot out of the top story without losing anything, but the same isn’t true for the subplot. So, if you take the principal story away from the subplot, you are left with something that doesn’t make much sense. If you can do so, you might reconsider which is subplot and which the top level story.
Plot your subplots separately from the overall story and weave the sections into the other story plots where they will work the best. My beat sheets are typically created in a spreadsheet. First, I complete the prime story’s beat sheet. Second, I complete the subplot or subplots as separate worksheets. Once, I do finish them, I create a combination spreadsheet where I list the beats in the first column. I put the beats for the primary story in the second column. The set up is, I put the subplots in the following columns. This method allows you to determine if a particular beat is the same in the central story as in the subplot.
This method helps to weave the story and subplots together seamlessly, which is the goal here. Characters in a subplot need goals exactly as they do in the primary story. These can be different goals or they can be flashbacks to a time when the character tried and failed to achieve the goal of the top level story. Each goal represents a different subplot.
How you choose to use or not use a subplot, remember a subplot is a plot in itself and is supported by the main story. Therefore, if you have a draft which needs something, consider adding a subplot. It can make the existing story stronger. Which is the function of a subplot, another tool in a writer’s work box.