You're carrying the single best tool to improve your presentation skills, and you might not even know it.

It's your smartphone. Since more than 70 percent of the population in the U.S. carries one, it's likely that you have access to a small screen and its recorder.  

Here's the simple process that will take your public-speaking skill to the next level. Take out your smartphone, prop it up or place it on a tripod to capture your entire body, and press record. Start your presentation. When you're done, press stop and watch it. It's that simple.

Very few people record themselves practicing a presentation, which means you'll stand out by using this tip.  

For example, this week a senior executive at one of America's largest companies is traveling to several locations to brief thousands of employees about internal changes to the way they do business. He's confident, clear, passionate, and persuasive. But he wasn't always like that. 

When I met with the executive recently to give him some public-speaking tips, his body language and vocal delivery failed to exude confidence. Although he's one of the smartest people you'll ever meet, he doesn't give a lot of presentations. He was chosen to speak about the project because he knows the most about it.

"You look down too much. You're not making eye contact. You don't use gestures. And your delivery is very slow and plodding. These are simple to fix," I said.

"Really? I have no idea I'm doing any of those things," the executive responded.

I showed him about two minutes of his presentation that I had recorded with my iPhone. I paused the video on every frame to point out areas where he could improve. He made the changes immediately. All he did was watch himself on video.

Although the executive had me by his side, you can catch the most common problems yourself. Pay attention to these five areas when you record yourself practicing a presentation.

1. Boost passion and energy.

A presentation is a contrived conversation. You're not talking in a lowered voice as you might be with your spouse at the kitchen table. For a presentation--especially in front of a large group--turn up the volume, kick up the energy, and put a smile on your face.

2. Use gestures.

Don't keep your hands in your pockets, folded in front of you, or rigidly locked to your side. And avoid crossing your arms. A speaker should have 'open' posture. It means keeping your arms uncrossed, hands open, palms up, and using gestures that reinforce your message.

3. Make eye contact.

One of the reasons you should rehearse is to internalize the message on each slide. The single worst mistake you can make as a presenter is to turn and read from the slides word for word (You shouldn't have too many words on a text, but that's the subject of another article). Most presenters don't even realize they're looking away from the audience by reading slides, notes, or looking down at their shoes. Keep your head up and your eyes fixed on your audience.

4. Avoid filler words.

Listen for words that serve no purpose except to fill the space between sentences. These are words like 'um' and 'ah.' Yes, it's natural to use a few filler words, but most of us use far too many. It's annoying. These days, I'm hearing "so" at the beginning of a lot of sentences:

"So, let's get started..."

"So, here's the next step..."

"So, are there are any questions."

You don't need 'so' unless it's in the middle of a sentence and acts a connecting thought. Don't start every sentence with it.

5. Avoid distracting habits.

Watching yourself on video is the best way to catch yourself scratching your nose, flipping your hair, or jiggling coins in their pockets. We all have habits that we simply don't notice until we see the way we look to our audience. If you fidget, you'll catch it on video.

You don't have me by your side when you're practicing your presentation. But with a simple video, you can catch the biggest problems yourself and fix them.