Interview questions, typically, are answered in two ways: the short version and the long version. When an interview question is open-ended, I always suggest to candidates that they say, "Let me give you the short version. If we need to explore some aspect of the answer more fully, I will be happy to go into greater depth, and give you a longer version."
The reason you should respond this way is because it's often difficult to know the detail of answer each question will need. A question such as, "What was your most difficult assignment?" might take anywhere from thirty seconds to ten minutes to answer, depending on the detail you choose to give.
You must always remember that the interviewer is the one who asked the question and so you should tailor your answer to what he or she needs to know, without a lot of extraneous rambling or superfluous explanation. Why waste time and create a negative impression by giving a sermon when a short and to the point prayer would do just fine?
Let's suppose you were interviewing for a Contracts Manager position, and the interviewer asked you, "What sort of contracts management experience have you had in the past?"
Well, that's exactly the sort of question that can get you into trouble if you don't use the short version/long version method. Most people would just start rattling off everything in their memory that relates to their related experience. Though the information might be useful to the interviewer, your answer could get pretty complicated and long-winded unless it is neatly packaged.
One way to answer the question might be, "I've held Contract Management positions with two technology companies over a six-year period and was a commercial contracts attorney at a private law firm for an additional two years. Where would you like me to begin?"
Or, you might simply say, "Let me give you the short version first, and you can tell me where you want to go into more depth: I've had eight years experience in contracts with two companies and one law firm, and hold the title of Contracts Manager at my current employer. What aspect of my background would you like to concentrate on?"
By using this method, you telegraph to the interviewer that your thoughts are well organized, and that you want to understand the intent of the question before you travel too far in a direction neither of you wants to go. After you get the green light, rather than a list of things that pop to mind, you can then spend your interviewing time discussing in detail the things that are important to the interviewer and to your obtaining the position.