How to ask great questions

From Asking Questions More Effectively by Mark Suster:

The ability to ask questions effectively is one of the most important skills in business as is the ability to actively listen.  Yet as important as these two skills are they really don’t seem to ever be taught in school.

The “Wide” (and uninterrupted) Question: 

You ask a very broadly defined question and intentionally don’t try to offer specificity in what you mean by the question.  It is designed to get the person you’re asking to reveal more than they would if your question directed them toward a more narrowly defined path.  There are definitely times where a more narrowly defined question makes sense and where you want to guide the person you’re talking with to a narrow boundary to elicit a certain type of response.  For extracting the maximum range of information in an interview nothing beats “wide” and nothing beats silence from your side.

Notes:
(1) Asking great questions is the key to interviews, reference checks, employee reviews, finding problems, and exit interviews. It can even help with motivating people and selling.
(2) Mark suggests that you ask wide and uninterrupted questions. But I’ve found that the best questions are open ended enough that you’re not anchoring the person answering the question, but specific enough that the question is easy to answer. For example, I have a friend who I see every weekend. Instead of asking “how are you?”, which is too wide for most people, and therefore elicits a bland or evasive response, he asks “How was your week?”.
(3) See: The questions Warren Buffett asked Bill Gates.