A subplot is a plot within your main plot, one that affects the secondary character(s).
Here are four basic points to keep in mind when creating a subplot:
- Is the character worthy? Does the secondary character you have chosen for this subplot have a deep enough personality to handle it? Is their life complicated enough to generate a subplot? Do they face conflicts that are separate from the main plot? If you can’t find a secondary character who is complex enough to generate a subplot, then you need to work on your characters to make them a little more three-dimensional.
- Does the subplot connect to the main plot? In order for the story to catch the reader’s attention, there must be inter-connections between the two plots. The characters must both have good, solid reasons to be in the book. They must have some proximity to one another.
- Does the subplot affect the outcome of the main plot? If your subplot only widens the scope of your novel, it’s not doing the job properly.
- Does the subplot range? Your characters don’t have to travel the world, but they should have a broad range of experiences within the plot and subplot.
And a final bit of advice: stick to one or two subplots. More than that will overwhelm your novel.