Last time, I provided some simple exercises so you could deliberately challenge yourself as a writer and deepen your skills. I ended with a promise to suggest more challenging work this time.
As a pure expression of story and one of the toughest exercises, I'd suggest creating a logline. You need to know who the protagonist is, what he or she wants, what the obstacles are, and what the stakes are. John Marlow provides an excellent tutorial on how to do this. You also might want to read my Problems with the Premise series.
You can dig more deeply into this by writing an introduction to the work (or a chapter), with the characters, situation, goals, and risks involved. If you want to have some fun and really push yourself, write it as a poem. Copy the form of a narrative poem or the best of epic poetry, if you wish. The Iliad? Not bad. But, for this exercise, I prefer doing something more like The Ballad of Gilligan's Island.
Something about expressing the essence of a story in rhyme provides focus and, as an extra advantage, gets your premise stuck in your head.
To know more about your characters, I recommend interviewing them. Character descriptions and lists of traits help, too, but they tend to be bloodless and a lot less fun.
To dig more deeply into a setting, visualize every detail you can. Use the best words for each object (goblet or tumbler, rather than glass). Qualify with textures, colors, light and shadow. This should be a long list. Now take in the other senses. Music? Other sounds? Odors? Drafts? Dank air? Is anything in motion? Changing?
Now, look at your list and highlight whatever will be noticed or will influence the protagonist (or other key character).
Finally, think about the setting in terms of the reader. In particular, look for two things: critical information and mood.
By the time you're finished the setting exercise, you should have a deep understanding both of the elements that come together to create a sense of place and how they impact readers.
Exploring theme is another classic way to poke at your story. It's too easy to come up with a "There's no place like home" answer, so I use an essay method. This can provide a real push to get to the heart of a story, especially after the first draft is complete.
One of my favorite exercises (and a very tough one) is to reverse or invert a solid, well-known work. The best example of this is It's a Wonderful Life, which takes Dickens's A Christmas Carol and replaces the miser Scrooge with the overly generous George Bailey. Nothing gets your head into the structure of a story more completely than this exercise.