Ask yourself two things before you start your design work:

1. What kind of story is this?  Scary?  Sad?  Happy?  About Halloween??

2. What color do you think of when you think about your story?  If it is a happy story, do you think of yellow?  If the story is set outside, do you think of grass (green) or the sky (blue)?

Finding a color that represents your story can be a good place to start your thinking.