To me a good preceptor is one that let's the student succeed and fail (to a degree). On my last day of OB rotation I totally fumbled with setting up a drip and moving fluids over. No harm was done, my preceptor stood and watched what I was doing, and when I figured it out, she said good job. When we left the patients room she took time to show me a few tricks to make it easier for the next time.
Never on that rotation did I feel rushed, scared, or intimidated by her. She wMade the learning experience priceless, and on top of that she is writing me a letter of recommendation to grad school!
A good preceptor is one who is calm, relaxed, and collected enough to watch a student fumble.