As a candidate for a job, boost your success rate by figuring out who and what the interviewer is seeking. Give up the idea that an interview is a test where "right answers" are the ones given by experts and "wrong answers" cause you to fail. There is no perfect score and, surprisingly, it is not a competition for the smartest or most expert employee. Don't misguide yourself by depending only on your own past expertise and experience. The interview is not so much about you as it is about what you have to offer the employer and how you will fit in.
That said, go to great lengths to prepare yourself before you get to the interview. Start by online and in-person research to discover what the people in this organization are dedicated to working on, such as their products and market-share, what kinds of people they hire and likely promote, and what their culture or values are like. In addition to proving your ability to work hard on what they want, you have to show that you belong. Think of the process more like a going on a first date or being accepted into a private club, rather than earning an "A" on an exam or getting into the right school.
With an ocean of talented applicants to choose from, employers are looking to fall in love at first sight. Just like you, if you'd be honest. They don't always do it in the most ordinary way, and often ask crazy-sounding questions like "If you were a leaf on a tree, where would you be? What's your favorite color? How inventive are you?" and "What are you reading?" as a way to separate out those whom they want to be with everyday from those they don't; those who can reinvent their jobs as times dictates from those who are inflexible.
When you hear an offbeat interview question, take a moment to consider what the interviewer is really asking. For example, the leaf-on-the-tree question quickly separates the highly ambitious and aggressive types (who'd boast a position on top) from the less confident, uncourageous folks (who'd admit to the low branch). Claiming a spot on a branch in the middle might indicate a level of comfort as both a leader and team player -- especially if the leaf were turned toward the light of the top leaf (the leader or boss) for inspiration.
As a candidate, you have the advantage if you understand that this line of questioning is also a way to examine your thought process, character, and creativity. Remember, there is no "right" or "wrong" here. As with any interview question, try not to panic or get flustered if you don't have an immediate answer. Instead, take a breath and consider your response before blurting out the first thing that comes to mind. A simple "That's an interesting question. Let me think about that for a moment," is often an appropriate way to buy yourself a bit more time to consider your answer.
For employers, a new hire has to be able to fit in and grow with the flow of the company. In truth, that has always has always been so. Despite laws prohibiting discrimination, employers have always coded their questions to determine whether they want you in their private club or not. And if you want the job with them, you have to prove that you can and will fit in.
Make your luck happen!