What makes a test question great?

We have all taken an awful lot of tests in our lives, and I bet most of them were lousy experiences. But I don’t think they have to be…do they?

This quarter I am a teaching assistant for a very large introductory biology class. One of my responsibilities is to write one to two test questions pertaining to each lecture.

So I know this is a very general question, but I was hoping you teachers and students could give me some help. What makes a test question a great test question? And what makes a lousy one, so I can try to avoid that?