Let us define fiction theme element as the “why” of your novel.  Why are you telling this story?  Theme is a concept that structures your story.  There are three areas that will lend further definition to your theme:  a personal dilemma, an event you witnessed, and your frustration with the way of things.  There are other ways to further define fiction theme element, but either one of the three sources mentioned here are a good starting point.

Personal Dilemma.  Personal predicaments define fiction theme element through your own crisis.  In this case, you will subtly weave your message through the story based on your perspective.  Let your characters’ actions, dialogue, thoughts, and ways of life weave your theme for you.

Event You Witnessed.  Events you saw, heard, or otherwise experienced define fiction theme element through that experience.  Again, your message will come naturally from the actions, dialogue, thoughts, and ways of life of the characters you create for your story.

Frustration with Social Situation.  Your personal frustrations at a social injustice (or other situation) define fiction theme element through your reaction, opinion, and proposed solution to the problem.  Do any of your characters represent the solution?

It is not difficult to define fiction theme element – it is difficult to convey it properly.  However, as you carefully develop a theme within your story, your literary agent will understand why you wrote the story in the first place.  More importantly, when you dig deep and further define fiction theme element prior to writing, your readers will appreciate uncovering the point of your story.