Sometimes when describing a thing, it is almost easier to describe what it is not. For example, consider the first paragraph to Tolkien’s The Hobbit:
“In a hole in the ground there lived a hobbit. Not a nasty, dirty wet hole, filled with the ends of worms and oozy smell, nor yet a dry, bare, sandy hole with nothing in it to sit down on or to eat: it was a hobbit-hole, and that means comfort.”
Notice how Tolkien doesn’t so much describe what the hole is as he describes what it is not? When he mentions a dirty, wet hole filled with an oozy smell and the ends of worms, I picture it precisely—just as the spade has opened a hole in the ground and chopped a worm in half.
In fact, by using this technique, Tolkien creates the barest image of three separate holes—two that do not exist, and one that he shall spend some time exploring.
I call this technique “negative description.” We simply describe something that it isn’t. “Marybelle wasn’t your mother’s kind of vampire, living in a crypt by day and sneaking into children’s bedrooms at night to suck their blood. Nor was she its modern counterpart—the sexy hip girl climbing trees in the forest and glittering in the morning sun. She was fat, and as her momma said, 'You come in a plain black wrapper, Honey child, and you got to accept that.' She tried to accept it, of course, she tried. But life ain’t no fun when you’re fat, and ugly, and you’ve got the blood Jones.”
In short, in describing any object, take time to consider how you can beat your audience’s expectations by comparing the thing that you want to describe with similar things.