Some say good presenters can visualize the audience naked, but I say great speakers strip for their audiences.

Great speakers and presenters are not afraid to bare their souls. They strip away all masks and illusions to allow audiences and prospects to see them for who they are. Audiences walk away not only with increased knowledge, but some insight into the presenter as a person.

Whether to sell, educate or inform, every speech or presentation must have a goal, and key to reaching that goal is generating trust. In order to trust us, people must know us, like us and believe we are credible.

Presenting speaks to one of our greatest fears—people may not accept us as we are. It's no wonder so many of us would rather eat glass than speak in front of a group.

Each person has a unique presentation style, and while some elements work well, others do not. Regardless of the presenters' skill, I have found most presenters can increase their likeability, credibility and authority by at least 25 percent by unlocking the “30-second window.”

Within 30 seconds, most of us form an immediate impression and then spend the next 30 minutes justifying our impression. Think back to a person you met on a blind date, first interview or social situation. Did you make a snap judgment as to whether or not you were going to like him or her? Most of us do.

We do it to others, and others do it to us. Most audiences decide whether or not they like us before we utter our first word.

For some, the “30-second window” is a breeze. These rare men and women have naturally high “likeability factors,” a face, smile or presence to which people instantly warm. Most of us, however, have to win audiences over, fast.

Five factors contribute to audiences' first impressions: gestures, movement, appearance, stance and eye contact. Of these, appearance, stance and eye contact are most critical.

Experts abound on the subject of proper dress and grooming for presentations, yet the best advice I found came from one of my seminar participants. She suggested looking into the mirror and noticing if anything stood out, and if it does, take it off or change it.

One man I coached loved loud ties. While his neckwear reflected his outgoing personality, it also distracted from his presentation. The audience focused on his ties rather than his face, missing much of what he had to say.

Like appearance, stance contributes to instant credibility, and for many women, stance is a challenge.

Most women are taught at a young age to assume a dancer's pose, feet close together with one toe pointed out at a 90-degree angle. While this stance may be feminine and pretty, it holds no authority.

Instead, I counsel both men and women, to stand tall, feet shoulder width and pointed outward, hands at their sides. While it is important to gesture naturally, hands should drop to the sides when not in use.

Stance is important in establishing credibility so don't hide it. At no time should speakers stand behind a podium, desk, table, or other obstacle. Great speakers allow the audiences to see all of them—physically as well as emotionally.

The eyes have been called the “windows of the soul.” As such, they are one of our greatest weapons in winning audiences. When it comes to eye contact, great speakers use a rifle instead of a shotgun.

I coach executives to begin their presentations by standing in silence, finding a friendly face, establishing eye contact, taking a deep breath and then beginning their talk. This simple tip helps speakers become grounded and start their presentations with authority. Many presenters talk while moving their heads from person to person like a sprinkler system, or worse they lose all connection with their audience by staring at one person, the slide screen or space. I train presenters to pick one person and maintain steady eye contact with that person until they have delivered a complete thought. Intensive eye contact can be uncomfortable, yet it is also highly effective in generating trust.

Discomfort is a constant companion for great presenters for they know no matter how good they think they are, they can always be better. Using appearance, stance and eye contact, they generate instant credibility while constantly challenging themselves to share more of themselves with their audiences.