This was the biggest problem with the pilot's performance that day. Confidence without the ability to back it up is useless, but if you’re truly competent, own it.

2. Candor

Truly professional people are forthright. They check the situation, calculate the risks, and offer a truthful opinion.

3. Self-awareness

This is a part of displaying confidence -- knowing who you are and where you fit in the world, and owning your strengths and weaknesses. If you do that, you can work to buttress the things you don't do as well.

4. Strategic thinking

One of the basic tenets of success is to start with the end in mind. Truly professional people identify their goals, then work backward to achieve them.

5. Anticipation

Just know that focusing on others' needs to the point that you can anticipate their challenges and solutions breeds confidence.

6. Caring

Related to anticipation: You can't truly help others if you can't bother to learn about their goals and fears.

7. Realism

"Promise me the world," the song goes. That may be a way to get the boy or girl of your dreams to pay attention, but it does nothing to make you look professional. Instead, promise the most you can, consistent with your ability to deliver.

8. Follow-through

See what I mean? These attributes are simple but not necessarily easy. Say you'll do something, then do it.

9. Enthusiasm

This one is inspired by reader comments , when I said Pollyannaishness was unprofessional. Smart enthusiasm, on the other hand, is a very positive quality. Colin Powell put it best: Perpetual optimism is a force multiplier.

10. Diligence

This is related to follow-through, but it's not exactly the same thing. Be persistent, demonstrate worth ethic, and check small things.

11. Performance

Nothing says "professional" like accomplishments, especially repeated accomplishments over time.

12. Discretion

Caring and self-awareness, combined with good communications ability, leads to prudence and the ability to be candid without giving offense.

13. Curiosity

No professional is ever finished learning.

14. Risk-taking

I hesitated to put this on here, out of fear of giving the wrong impression. Risk-taking doesn't mean being risky in the negative sense. Instead it’s about the realization that all courses of action involve some risk, and balancing that realization against the paralyzation of inaction.

15. Humor

You don’t need to be hilarious, but you need a sense of humor; it demonstrates perspective.

16. Fitness

This is unfortunate but true. If someone looks as if he or she doesn’t care about their health, it’s a lot harder to project professionalism -- and with it, the notion that they care about other things.

17. Authenticity

It’s good entrepreneurial advice to “fake it till you make it,” but your performance needs to be grounded in truth. Otherwise, no matter your skills, your deficits, your interests -- or frankly, even the things you aren’t interested in -- people can tell.