We all know what "body language" is - facial expressions, movements and posture. When you're watching someone you're talking with, these non-verbal clues often tell you how they're really reacting to your message and how well you're communicating.

Understanding body and face language is a powerful tool and I've studied it for several years. In fact, I've spoken on the subject to numerous law firms and consulted with individual defense attorneys to help them better understand what witnesses may be saying non-verbally.

It's wise to be alert to body language, but don't get too uptight about it. Body language isn't a perfect science. Let your instincts take over. Some people's body language, for instance, can fulfil all the so-called "good signs" that are supposed to encourage you.

They'll give you a firm handshake, look you straight in the eye, appear to be totally attentive - and be the most two-faced humans alive. On the other hand, some people who are sincerely interested and really listening to you the most closely might be walking around the room and staring out of windows - it's just the way they do their best listening and thinking.

A few years ago, I needed to accomplish a complex, long-standing goal. It was crucial to me. I'd been told about a man who could help me, but I'd never met him and I set up a meeting.

During our meeting, he was always looking around at everything but me. He'd fidget and tie his shoelaces, or he'd get up and pour a cup of coffee or he'd stare off into the distance. If there was a lull in the conversation, he'd talk about my car or something else that was way off the subject. Sometimes, when he was sitting, I got the notion he was half asleep.

In short, nothing in this man's body language could make me believe that he was interested in a word I was saying. Yet, I somehow sensed I could count on him to give me the help and expertise I was after. I just felt it.

It was amazing. Months later, this man's recall of our conversation was total. He'd taken it all in -even things I'd forgotten. His perception of what I needed was outstanding. He'd gotten it exactly right. And the job he did for me enabled me to accomplish my goal far better than I had thought possible.

So what did this tell me? It told me not to be too exact about trying to interpret body language. Understanding body language is a tool, as I said, but it is not necessarily the decisive one. At some point, your deep-down instincts will process everything and you'll just know if you're communicating successfully. Let your senses be your guide.

That's one of the best real-life rules I've ever discovered.