At some point, I'm sure you've experienced that heady feeling of satisfaction when you were asked to do something off-the-cuff and you knocked it out of the park. It could have been something as simple as saying a few words to a small audience or something as nerve-wracking as getting up onstage to deliver an impromptu talk. It's a good feeling when you can actually pull it off. For most people, though, it's the exception rather than the rule.

No doubt you've also experienced that sinking, nauseous feeling of being unprepared at a critical moment when all eyes are on you. To outsiders, you may have looked cool and collected. It may have seemed you oozed confidence and charisma  but on the inside you were a bag of nerves, feeling like a total rookie. It was hard for you to think about anything other than how you were feeling -- scared, anxious and flying by the seat of your pants. In such cases, all you can think about is whether anyone noticed you messing up; or how much better you'd be if you were prepared. It's a horrible feeling that lingers, and yet speakers of all stripes find themselves in situations like that all the time. The worst part is it's completely avoidable.

To be sure, being charming and personable is a great quality to have. But if you're a speaker, being a good schmoozer is not enough to wow a crowd. It may be great at a dinner party, but not in a high-stakes situation where people plop down money - lots of it in many cases - to hear you speak. Too often, speakers get in front of audiences without writing out their content, rehearsing their speeches or fine-tuning their delivery. And of course, it shows.

No doubt, there's value in being able to improvise. Sometimes, when technology doesn't cooperate or an external condition throws a monkey wrench into your well laid-out plans, it's good to be able to pivot. Too often, though, speakers rely on charisma and charm to move audiences, and they fail to do the necessary work to up-level their presentations. As a result, they don't know their audience, they don't write out what they are going to say and they don't rehearse. In short, they wing it. And that's a disservice to their audiences.

The pros know there's a difference between being "spontaneous" and being prepared. No matter how long they've been speaking professionally, no matter how many times they've given the same talk, they know there's always room for improvement. They're constantly tweaking and updating their material to best serve the needs of their audience.

If you want to be seen as a pro (and not as an amateur), here are three things to keep in mind before every talk.

1. Know Your Audience

If you don't know who you're talking to, how do you know what you're supposed to say? Knowing your audience is key to getting your message right. The language you use and the concepts you unpack will be different different for an audience of lay people, than an audience of scientists. Knowing your audience well will go a long way to creating a great talks that leaves a lasting impression.

2. Write down what you're going to say

In other words, script your speech or talk. When you can see your words on paper (or a computer screen) in front of you, it's much easier to organize your thoughts. You can see where concepts connect, where you can bolster an argument with stats or anecdotes and where you can get rid of things that don't serve your overall message. More importantly, you can also plan the two most important sections of your talk - the opening and close.

3. Rehearse

Top comedians, world-class athletes and award-winning artists all do this. They never walk onto a field or take the stage without having practiced or rehearsed. They understand that to give an exceptional performance, they need to be well-prepared. If you want to be seen as a pro, practice is a must.

Your Turn

How well do you know your audience? How often do you rehearse? How well do you prepare for high stakes presentations? Share your thoughts on Twitter or in the comments.