Read this list of guidelines from John Sawatsky, expert on the art of interviewing.
Getting the Goods – Interviews that Work
Smart Question Strategies by John Sawatsky
The best questions, argues Sawatsky, are like clean windows. “A clean window gives a perfect view. When we ask a question, we want to get a window into the source. When you put values in your questions, it’s like putting dirt on the window. It obscures the view of the lake beyond. People shouldn’t notice the question in an interview, just like they shouldn’t notice the window. They should be looking at the lake.”