Writing is a three-legged-table. The first leg of character develop helps the reader relate to your characters. They can see them grow (or degenerate) as the story moves along. It is critical that the characters have flaws…people relate to human faults.
The second leg of writing is plot. This tells your reader what happened. For example we see Luke Skywalker lead his father back to the good side. In Lord of the Rings we see Frodo’s struggle with the ring and Aragorn’s decision to take his place as king.
The last leg is called World Building. World Building is the act of putting together a setting in which your stories take place, weather that be middle earth or a galaxy far, far away.
As you begin to write, think about these three things, and reveal a little more about each to your writer.