Well, one way is to think about your own dreams and strange experiences. Sometimes, they can be the basis for an amazing fantasy tale. Also, observing nature and imagining magical elements within it can give you great ideas.
To write the main idea of a story, think about what the story is really about at its core. Is it about love, adventure, or self-discovery? Once you figure that out, summarize it in a clear and concise sentence. For example, if the story is about a character's journey to overcome their fears, the main idea could be 'A character's courageous battle against their deepest fears to find inner strength.'
The main idea of a story can be written by looking at the beginning, middle, and end. Consider what problem or goal the characters have and how it gets resolved or achieved. Put that into a simple statement that tells the reader what the story is mainly about.
Start by identifying the core theme or message of the story. Then, summarize it in a clear and concise sentence that captures the essence. Place this at the center of your story map.
Start by thinking about the key events and characters. What is the most important thing that happens in the story? That's usually a good start for the main idea.