I recently read an excellent article about sub-plots written by Anna from Shout with Emaginette. I'll share with you the sentence that stuck with me (slightly paraphrased):
If the plot is a section of fence, the sub-plots are the vines that grow upon it. The more vines, the more color and the more intertwined action.
I mulled that over for a couple of days, since one of my current projects is in first person. I came to the conclusion that in order to create those vines it would have to be through the eyes of the main character and how she/he perceived other characters and events. Her/his ideas, thoughts and feelings would have to react with other characters to create sub-plots around those characters.
Since in first person we only know what our protagonist knows, it seems the challenge would be to make sure the vines intertwined enough to create action so the story doesn't bog down. I decided to make one of my sub-plots around a secondary character who has an agenda to hurt the protagonist. In order to create suspense, I wrote him as being sullen and then openly hostile, but without any direct threats towards the protagonist. Also, the protagonist can overhear his plans as he talks to someone else.
It is fun and a challenge to work in first person. I'm hoping that all the vines intertwine and make an exciting story for my readers. If nothing else, it will be an educational experience for me. One that I haven't had since I was in my last writing class in college.
How do you create your sub-plots? Are they created around different characters? How do you relate them back to your protagonist?