I'm reading a book called I Is an Other, about the uses of metaphor. Geary points out that language is metaphor, that much of what we think of as direct terms for an object are just defunct metaphors. ("Table" actually started as a metaphor -- something that stands.) When something new comes into our knowledge, we don't usually invent new terms for it, rather we apply or modify a term of something it's related to. (I'm thinking-- back in the dawn of the computer era-- small pieces of information were called "bits," and "bites" or "bytes" are ... bites of the bits. A "bug" is a computer problem, based on, you know, a fly in the ointment. :)
Metaphor is completely inescapable for human discourse, and actually makes possible not only the acquisition or invention of new knowledge, but also nuance, subtext, theme, linkage, motif-- all the deep stuff. Fiction IS metaphor, and I think we don't write good fiction really until we understand that consciously or subconsciously.
Some writers seem to think that fiction is just facts we make up, kind of like really dishonest reporting-- just narrating what happens, only it's not really happening.
But no matter what you're writing, it becomes fiction I think only when you let metaphor in, that what you're writing means more than what the direct words say and the scenes show. Let's take an example most people will know-- the XMen. The Xmen are mutants, shunned by humans, and they have special powers. Right away we have a metaphor there, diversity as strength, maybe. Then look at their powers and think about how the powers connect to their personalities and conflicts:
Cyclops: With the vision that burns, he must wear blinkers to protect others. But being blinkered, he often can't see what's right under his nose, like his wife's problems, or his teammate's feelings.
Rogue: She steals other mutants' powers. She can become anything, but she can't touch anyone. She's the ultimate "vampire," really, her strength comes from depriving others of their strength.
Gambit: He doesn't have much in the way of power (those cards are lame :). He does have the ability to charm, and while that's an otherworldly charm, it's an analogue to his insouciant human charm.
Wolverine: Adamantine claws, yes. But metaphorically, that's a symbol of his anger, which is dangerous to him and others.
Professor X: He is crippled physically, but he can read minds and so has access to others' thoughts. This telepathy is a manifestation of his unending curiosity, which makes all of the universe's knowledge accessible to him because he actually seeks it.
Storm: Her ability to "control" the weather is a counterpart of her need to control her own inner wildness.
That's just an example, but from pop culture, just to show that metaphor isn't restricted to literary fiction. I suspect, in fact, that what makes a story popular is that its metaphors make sense subliminally to a whole lot of people, tapping into some universal theme or need within humans.
I'll keep reading and come up with more examples. (He uses Elvis a lot.) But the message is-- think of story as metaphor. It's not just the narration of events (though it's that too). It's got some meaning or meanings buried maybe not too far under the surface. How you name your characters, what you have them do for a living, whether they slam a door or close it quietly-- all these can be metaphors for some deeper truth.