According to Lou Adler, the author of "Hire with Your Head," all you need to start with is one basic question: Can you tell me about your most significant accomplishment? This particular query will allow you to peel apart job candidates' interview answers like an onion until their true self is revealed.
Once a candidate starts answering, you can glean many more vital details that will separate the prospects from the pretenders. For example, you can follow up with several related questions, such as: Why were you chosen for the task? What technical skills did you need? What are some of the major decisions you made? What are the challenges you faced and how did you deal with them?
This one-question approach - called "performance-based hiring" - will help you slip past slick presentation skills. It might also help you uncover those diamonds in the rough who may not be the most interview savvy, but possess the attitude and abilities you want on your team.
To find out more on the subject, Google the term "performance-based hiring," where you'll discover several useful articles. Additionally, books such as "Hiring the Best" by Martin Yate and "How to Hire A-Players" by Eric Herrenkohl will assist you in recruiting the best candidate, not just the best interviewee.