I work with many public speakers who ask me varying forms of the same question: how can I get over my anxiety of public speaking? My answer is always the same: "At the risk of sounding like Captain Obvious, the only way to get over your nerves is by being prepared."

It sounds deceptively simple, I know. That's because it is. Sometimes the answers to our most vexing questions are so blindingly obvious we completely ignore them. That's because humans have what's called "inattentional blindness", the inability to see something conspicuous when focusing attention on something else.

Harvard researcher Daniel Simons and his student Christopher Chabris discovered this tendency for selective attention while conducting the now-famous, 60-second "gorilla experiment" in the late 1990s. In the experiment, a woman dressed in a full gorilla suit walks through a group of volunteers passing basketballs. The participants watching the group were asked to count the number of times the basketball was passed among the people wearing white shirts. As it turns out, half the participants were so focused on the basketball, they completely missed the gorilla.

Similarly, when all your attention is focused on feelings of dread, anxiety and fear, you block out some obvious ways to overcome those feelings. There is no more obvious way to gain the confidence and courage to face a crowd than by being prepared. Winging it won't cut it. The more prepared you are, the better you'll perform.

Don't agree? Consider this study by researchers at the University of Alabama who wanted to see how preparation affected the confidence and nervousness of witnesses testifying. Half the study participants received "preparation training" for a mock trial. The other half did not. Participants were asked to rate their level of confidence and nervousness before and after the trial. Not surprisingly, those who received preparation training said preparation "led to strengthening in confidence for both direct and cross examination, whereas participating in testimony simulations without training did not lead to a significant strengthening in confidence."

Not only does preparation help calm your nerves, it'll also help you nail your presentation because you'll know exactly what to say, what works, what doesn't and what you want the audience to leave with.

Here are three ways you can prepare for your next (or first) presentation:

1. Write out 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.

2. Edit and refine.

Sometimes speakers want to cram as much information as they can into a presentation. Resist that temptation. Be merciless about editing your content. The editing process is the most critical part of your preparation. Don't skip it. The more clear and succinct you can be with your words and ideas, the more your audience will value what you have to say.

3. Practice, practice, practice

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.

It's Your Turn

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