One simple way for an author to develop a story theme is to use the process of writing to figure out what the story is about at its core, then hone the writing to reflect that theme more closely. Themes are often deeply held ideas or beliefs that the author wishes to convey to the reader.
Developing a theme for a story requires an author to dig deep into the concepts of the story being told. The theme defines to the reader what the story is all about, so in the development stage, the author considers this question and comes up with one or more answers, which become the story theme. The theme is a narrative that is woven throughout the story in various ways. It is a powerful idea that helps to drive the plot and character action. Themes are memorable and leave the reader with something to think about after the story is over.
Themes are usually narrow in focus and may be expressed simply then developed through the narrative. It's common for themes to be about issues people face in everyday life. Good versus evil is a theme featured in many stories. Authors typically consider what story they intend to tell when figuring out their themes. For instance, a story about a young boy growing into manhood expounds on a coming-of-age theme.