We all know that the first 10 to 20 seconds after you meet someone are crucial. In that time, you determine a lot about how much you like and trust someone. Just how important are those first few seconds? For 90 percent of people that impression remains unchanged even after hearing the person speak, according to Noah Zandan, president of Quantified Impressions.

Are you surprised by this? You may think you are evaluating someone based on the content of what they say, but in reality, most of us would stick to our original judgments. Then we just pick and choose portions  of what was actually said to support our original point of view. In fact, one study showed that people who watched job interviews for just a 15 second video, including merely the greeting and a handshake, evaluated the candidates almost identically to the people who watched the whole interview.

Does this mean you should stop the interview process and simply invite in a slate of candidates, shake hands with all of them, and then make your decision? It would definitely save time, and you'd probably pick the same person anyway. First impressions are that important.

But what if you wanted to be better than 90 percent of hiring managers? What if you wanted the best person in the job, not merely the one who took a course in body language? Not all jobs need someone with fantastic body language, so why give that particular characteristic so much power? Here are some ways you can be in that 10 percent of hiring managers--people who can make a real judgment.

Create your criteria before the interview. If you already have written out exactly what you are looking for, what skills are important and what problems your company needs to be solved, you'll have a clear idea of where the interview should go.

Take notes. These notes allow you to look back after you've had some time to clear your mind and after you've met several candidates. Write down what eacg candidate said, and match it up against your criteria. It will help you make a match.

Ask others to help evaluate. If you have your candidates help solve a problem by making a presentation, or writing some code, have someone who wasn't in the room take a look at the written documents and ask them for their opinion. Remember, presentation skills are far more important for people who have to present than they are for people who will be behind the scenes. Letting someone you trust look at the behind-the-scenes work product will also help.

Count your "yes, buts." If you respond to a colleague's assertion that "John's stronger on analytics than Jane is, and we really need strong analytics," with "Yes, but..." it may be an indication that you are going off that first impression rather than the actual facts gleaned from the hiring process. If it's "Yes, but Jane can also do X, Y, and Z which are also critical skills," it's probably a sound analysis. If it's simply, "Yes, but Jane seems like the better candidate," slow down and try to see if you're making your final decision based on a handshake.