I've heard a surprising number of remarks lately from writers who find description a difficult task. Some wish they could layer in more setting, others feel they go overboard. So how do you strike the right balance?
Voice and Pacing
Most obviously, choose the level of description that suits the story's voice, the narrator's voice, and your voice. Sparse prose needs few descriptors, beyond a hint or two to set the scene. A great deal can rely on the reader's own associations filling in the blanks.
If your style is rich and vivid, or your images need more description (unfamiliar locations, alien races, unusual costumes), you can take a little longer to weave your descriptions, and add more detail. Just beware how long others may be willing to read before they start skimming.
Instead, space things out among relevant action and information. Slip them into movement and action, spread a character's description out over a whole chapter.
Description can't just describe things. It needs to do something.
Don't just describe the boss's hairy arms, but how your protag would love to rip those hairs out. Set the scene in relation to the conflict at hand, or use it to pique curiosity. Tension carries a story not just from page to page, but also from paragraph to paragraph. Give your descriptions more purpose than just window dressing -- lead them toward plot points, character motivations, internal conflict.
Since I could spend all night thumbing through my favourite authors for examples, I hope you'll forgive an example from my own WIP, where page numbers come easier:
Old chipped vases, bronze things green and unidentifiable with age, sat on ledges down dim corridors. Innumerable bits of weathered metalwork escorted me where I hazarded a lord would keep his library, and I could have snatched any number and been off without raising an alarm.
Farther on ornaments bore ancient bits of gem and precious stone, some as large as sovereigns, and I hesitated. I could take three, five, a dozen perhaps, and the gems alone would fetch enough to bribe a Guardsman, barter passage with the Wayfarer’s Guard. It was the safer bet. Any thief would do as much -- but one hadn't.
They're tiny questions but each paragraph has one that leads to the next, and the descriptions come in the context of movement, and things relevant to the character. The point of the scene keeps moving forward.
The appearance of a new character makes another easy culprit for grocery list descriptions. We love our characters, and we want to ensure people share the exact same image of them as we have. Really though, how many do we hang on to?
To quote Stephen King (who has many other marvelous things to say on description, all of which you should read. Right now -- no wait, after this post): "If I tell you that Carrie White is a high school outcast with a bad complexion and a fashion-victim wardrobe, I think you can do the rest, can't you? ... We all remember one or more high school losers, after all; if I describe mine, it freezes out yours, and I lose a little bit of the bond of understanding I want to forge between us."
A few well-chosen details usually do the best job, and, as King points out, those details will probably be the first to spring to mind. For my antagonist, it's all about the mouth, for another it's thin lips and receding hair. Receding, yes, but I couldn't tell you the colour. That never seemed to matter. After your basics, a few character quirks will fill in the rest on their own. If the they stick around, drop another line or two later on and flesh it out.
With arms clasped behind his back, Durance looked me over, twisting a heavy gold ring on one finger. I stood stiff under his scrutiny, returning the same. Little older than Shaw, privilege left Durance slim and soft of line, swaddled in fine velvet. But they shared one thing in common, master and servant—neither gaze missed aught of note. Not my worn boots, not the patch of flesh glaring beneath my rent tunic, torn over an inch below the collar bone.
There's not much description here, but I don't think you'll be lost without his eye colour. I think later I threw in a reference to hair, but only because he was wrenching it all out of sorts.
Do descriptions give you trouble or do they come easily? How much description can you read before you start to skim? Are there specific types of description (character, setting, movement, action scenes) that give you trouble?