The operative word is act. Feeling confident can take years. Acting confident, which is important in most business interactions, doesn't have to take long to learn. Are there any special considerations if you're an introvert? "We know from the research that introverts tend to be less outgoing," says Navarro, who describes himself as an introvert in the manner of the late talk-show host Johnny Carson. Navarro says he "really, really prefers to be alone or only in small groups." He likes to read, walk, and kayak solo, and he's not a big partygoer. However, Navarro adds, "As needed, we perform what we have to do to accomplish our job or mission."

So how do you appear confident even if you're low key by nature? "Look at Secret Service agents," says Navarro. "They exude confidence while being very demure. You don't have to gesticulate a lot or act out to be noticed or to lead. You do have to be visible, you do have to have posture, you do have to have situational awareness. But all of these things can be adopted and perfected."

How did Navarro learn to project his sense of confidence? "When I was young I looked at people like Cary Grant and I adopted behaviors from him that I thought would be useful." He continues, "I know a lot of people who think the nonverbals of Colin Powell are exceptional - they are. Here is a man who is very soft spoken and yet nonverbally he commands respect, as I noted in Louder Than Words. This is all based on his dress, grooming, and bearing."

What can you do to convey confidence nonverbally? Drawing on insights from Davidson and Navarro, as well as my own work coaching clients to improve their presentation skills and job interview skills, follow these ten tips - with special insights for introverts.

1. Rest up, prepare, and practice. This mantra can come in handy for anyone. However, introverts benefit by resting up during their quiet time to refuel their social energy. Preparation and practice are essential for introverts because we are less inclined than extroverts* to think on our feet. Also, we're not multi-taskers by nature. So the better we prepare for job interviews, negotiations, presentations, and other meetings, the more likely we'll come across as confident.

2. Make a positive first impression. As I shared in my book, Self-Promotion for Introverts®, a study at the Massachusetts Institute of Technology states: "Decades of research in social psychology illustrate the surprising power of first impressions. From contexts as diverse as evaluating classroom teachers, selecting job applicants, or predicting the outcomes of court cases, human judgments made on the basis of a ‘thin slice' of observational data can be highly predictive of subsequent evaluations. Here's why this is particularly important for introverts: we don't make fast friends. Instead, we take our time to build relationships over time. That's fine. But don't forget how you come across - from head to toe - the moment you walk through the door.

3. Keep your cool. "Great leaders don't get agitated," says Navarro. "They don't yell and scream and they don't throw fits." Instead, he adds, "They try to conceal emotions, they don't belittle others in public, they are cool and calm. And all of these things can be learned and modeled and actually fit quite nicely with being introverted. But to lead you must be seen."

4. Listen attentively. Introverts spend more time listening than talking. Use the information you glean to your advantage. You'll come across as more informed and more confident. Ask questions to learn more.

5. Stand up. "You're sitting at your desk and a demanding person enters your office. What do you do?" I ask Davidson. "Stand up immediately," she replies. That puts you on equal footing.

6. Command your space. "When we are confident and comfortable, we spread out," says Navarro in his book, What Every Body is Saying. Davidson offers an example: "You can gesture by extending your forearms."

7. Stand with your feet apart. Davidson recommends a wide stance with one foot forward pointing in a direction to suggest "some dynamic motion," she says. Navarro's writing is a treasure trove of information on the language of the feet and legs (and on up!). He goes into depth about this in his popular book about poker tells, Phil Hellmuth Presents Read ‘Em and Reap. In fact, Navarro believes that feet are the most honest part of the body because, as he says in the book, "the behavior is a limbic brain response that has been hardwired into our nervous system during an evolutionary period that spans millions of years."

8. Interject. Boisterous meetings and networking events can be especially challenging for introverts. How can you project confidence? Interject. Lean forward, raise a finger, make eye contact with someone who is speaking, say her or his name, smile, and just jump in. You may not like to interrupt anymore than you like to be interrupted. However, I can tell you from my days on Wall Street, if you don't interject, you can appear worse than under-confident - you'll become invisible.