dancinghorse has a nice article on writing description in this month’s Reflection’s Edge.
Among other things, she touches on what I think is one of the most important things about description: depending what sort of a narrator you’re using, description much of the time doesn’t exist in a vacuum–a description reflections upon, and illuminates, not only the thing being describes, but also the being doing the describing. (Maybe all the time–even omniscient narrators are not completely without viewpoint, generally.)
For example, you can say, “The Targs attacked Zamora and conquered it.” Or you can say, “The bloody Targs wiped out my frelling city.” Or, “Alas, my lord, the Targs have come; Zamora is no more.” Or, for that matter, “General, we did it; we took Zamora!”
Also:
We seldom, if ever, need a catalogue description of any character. The right two or three details will convince readers that they know exactly what a character looks like – even if they’ve never actually been told the color of his eyes or the shape of his face.
And you know, it’s okay if every reader who’s convinced they know exactly what the character looks like has a completely different image in mind–so long as all those images fit with the nature and personality of said character.