You have a presentation, an interview, or an important meeting. You're well prepared; you know your subject inside and out. But you're feeling nervous. You tell yourself you're going to be fine. But in the end, your audience isn't convinced that you know your stuff. What's happening here? Body language, that's what!

A few years ago I was coaching a company vice president who was readying himself for a meeting with the CEO, who happened to be his father. We videotaped the prep session from the time he opened the door to enter the room until he sat in the chair to begin the practice conversation. At that moment I cut the taping so that he could watch what he'd just done. He had entered with his shoulders slouched, head down and tilted to the side, eyes on the ground. The message?  Submission. He had no idea he had been holding himself that way until he saw the video.

We're always communicating on two levels, the physical and the verbal. And while what we say is important, the language of the body has far greater impact. And what's more, we're generally unaware of the messages we're sending.

The next time you feel unsure of yourself even though you're well prepared, here are 5 things you can do that will not only show confidence, they'll help you feel confident.

1. Walk into the room with your head up and shoulders back. No shrugging or head tilting. Women often tilt their heads to the side and down slightly. That signals submission, uncertainty, hesitancy.

2. If you are walking with a notebook or papers in your hand, have them in one hand by your side. Swing your arms slightly as you walk. That conveys assuredness. Whatever you do, don't clutch whatever is in your hand to your chest. That sends the message that you're fearful and protective.

3. Look around the room as you walk in, making eye contact with many. Smile slightly and nod to people, even those you don't know. That immediately connects you to the crowd and draws them in. Do not stare off into space, look up, down, or toward the wall. You must create relationship from the get-go.

4. When you greet someone and you're about to shake hands, first step in with your left foot, then cross your right foot over your left very slightly as you lean in to extend your hand into the shake. It's a confident move and equalizes the power right away.

5. When you stand to speak, hold your shoulders open with arms at your sides. Your arms should be bent from 30 to 90 degrees at the elbow. That signals openness. Whatever you do, don't fold your arms across your chest.  That's another protective move and signals closure to new ideas. And if you hold your hands behind your back, the message is one of mistrust.

Practice before you put these into play. Videotape yourself and/or have a friend watch and give you feedback. You'll be feeling much more confident in no time.

Note: Tip #4 has been adapted from The Definitive Book of Body Language by Allan and Barbara Pease.