What makes a good user document?

That's the question I'll be asking myself this week. I have been asked to be a "remote judge" for a technical communication competition. In the judging guidelines it states:

"Two judging criteria are basic in the competitions:

- Judge the work the contributors actually did.
- Judge how well the work does what it is intended to do."

It will be hard work (the entrants deserve a proper critique) and fun at the same time.