A couple of my writing friends have been talking about how to know what to describe, and how much setting you really need to throw into your work. I have fairly definite ideas about this, so thought I'd outline them here. If there is one thing that frustrates the hell out of me, it's too much description or setting detail. But equally frustrating is not enough.
In terms of description, you don't need to describe everyone or everything. If they are important to the story, then describe them. To use an example I used the other day, if in a scene a character is startled by a car driving by too fast, and that's the only time you see the car, you don't need to describe it in any detail. If though, that car comes back later in the story, filled with thugs who kidnap the MC, then describe it the first time we see it. By taking the time to show us details of the car (crumpled back bumper maybe, dangling headlight, whatever) you're giving it an importance, showing the reader the car is important to the story and should be remembered for later.
In terms of setting, I'm a great believer in not giving the generic details. We all know what an office cubicle looks like. But what makes this particular office cubicle different? What can you tell us about it that shows us who works in there? Describe the precarious piles of paper drifting across the surface of the desk. Describe the lewd picture the guy uses as a screen saver. Describe the neatly lined up jars of pencils and pens. Whatever makes that cubicle belong to the character who works in it. You'd be amazed how much you can learn about a character with just a few details of their environment.
How do you like to use description and setting?