I was recently keynoting at a company when the presenter before me (an ex-Navy SEAL) took the stage to discuss the importance of succeeding under extreme pressure. It was a topical comment, as this particular company was about to go through an intense period. He shared an training overview video from the Navy SEALs detailing a particularly onerous part of their training--what's known as the underwater competency test.

It's a test most SEAL trainees fail on their first attempt, and it features an exercise partially shown in the video, where instructors "attack" scuba-geared trainees underwater, tying knots in their air hoses, ripping masks off their faces, and causing general mayhem. It's intended to help the SEALs be ready for any underwater situation. A 2009 History Channel program entitled The Brain first detailed this specific exercise, an exercise that only 25 percent of Navy seals were passing.

Until the Navy injected psychology and brain science.

Because so many recruits were failing the extreme underwater test, even with four attempts to pass, the Navy sought help from psychologists and devised what one instructor (who was featured on The Brain) called "The Big Four": four psychology-based methods the SEALs could employ to help them get through the intense situation successfully, without panicking and coming up for air before the 20-minute session was completed. Pass rates for the training increased from 25 percent to 33 percent.

The four methods are powerful for anyone who has to weather a high-pressure situation.

1. Goal setting.

Specifically, setting goals in very small increments, then tackling one goal at a time. One former SEAL said this was the approach he took for the entire intense training period--make it to lunch that day, then the next goal was to make it to dinner.

I used this technique regularly in my corporate days when it came to achieving extremely difficult, pressure-laden goals. I'd break a big goal into a series of micro-goals. Then, when I was in the midst of the highest-pressure parts, I'd leverage achievement of the previous micro-goal to give me a boost of confidence and energy to attack the next one.

2. Mental rehearsal.

This is also called visualization, working at something over and over until it comes naturally and so that it's easier under extreme duress. The Navy SEALs want their candidates to succeed in a real-world, terrifying, underwater situation, so they make them practice being under duress, without oxygen, to learn to fight one of the most fundamental human fears--drowning.

Now, giving a keynote is hardly this stressful, but it is definitely a high-stakes situation. The No. 1 thing I do to lower the stress levels of any keynote and to better enable me to succeed is mental rehearsal. I practice the keynote over and over until it feels second nature. I visualize the audience engrossed in what I'm saying, taking notes, or any number of other positive visual cues.

When you do enough mental rehearsal, muscle memory kicks in and you don't have to concentrate on trying to remember what you were going to say. Instead, you're freed up to focus on putting energy and passion into your performance. It's this simple--you want the brain prepared and familiar with the high-pressure situation you're going to be in. Familiarity nets flourishing.

3. Self-talk.

Our brains can quickly take us into very unhelpful places when we're panicking. Imagine the conversation you're having with yourself when you're 15 feet underwater and your air hose is knotted in three places. But the SEALs ae taught to recognize that we speak 300-1,000 words to ourselves a minute and so it's about changing the nature and tone of those words.

I've found in high-stress situations it's more important than ever to omit tones of panic and catastrophizing and replace them with a more focused, "let's just do what needs to be done right now" dialogue.

4. Stay calm.

It's important to stay cool and to specifically focus on your breathing. I would imagine it's hard to focus on your breathing when you're underwater and you can't, but when coupled with the ability to stay calm, it's a powerful duo.

I can't say I get nervous anymore, even before a keynote to thousands of people (see point No. 2 above). But just to be sure, two minutes before I go onstage you can find me focusing on reaching a calm, centered state, and breathing slowly, aware of each breath and exhaling slowly.

Staying calm in any tense situation is easier said than done, but I can tell you first-hand, with practice, it really is a habit you can learn.