Always provide LOTS of details when asking a question. No detail is irrelevant.  
  
Far too often I see questions with not enough detail to get a good answer, but never have I seen a question that includes too many details.  
  
(Example of "no detail is irrelevant": I heard about a video-processing system that would intermittently fail while in development. Some days it would work properly, and some days it wouldn't, with no change in system variables/updates. Eventually they figured out that when the developers wore plaid shirts to test it, it didn't work because the system couldn't process the complicated pattern and gave up. When they wore other shirts, it worked fine.)