There are many aspects to this. Sometimes you are working from a script (not shown here), and sometimes you need to come up with a story on your own...
Miles to go before I sleep.
Brief 1: Hulk vs Superman. One has to win. Tell the story.
Brief 2: girl unwilling to go to school until she gets her coffee. I expanded that to include moments of exaggerated drama that is characteristic of this girl.
Color scripts are another way to visualize your story. This one was done in pastels and illustrates the tragic story of Lucy Gray.