I'm writing this column during the NFL playoffs, when some teams stunned their opponents with an unexpected victory. The San Francisco 49ers shocked Green Bay Packers fans with a win on the frozen ground of Lambeau Field, while a rookie kicker for the Cincinnati Bengals drilled a 52-yard field goal to beat the top-seeded Tennessee Titans.

When Bengals kicker Evan McPherson took to the field for a field-goal attempt that would win the game, he turned to the team's backup quarterback and said, "Looks like we're going to the AFC Championship Game."

McPherson achieved what West Point psychology professor Nate Zinsser calls "First Victory." I talked to Zinsser about his new book, The Confident Mind. He told me that First Victory was coined by military strategist Sun Tzu. It means that you have unshakable confidence, a sense of certainty that you're prepared to meet the challenge ahead.

First Victory requires confidence and competence. It's when preparation meets the moment.

Bottom line: You can practice all you want, but if you don't believe you can do it, you'll still fail to perform your best when the pressure is on.

I've seen the damage that failing to achieve First Victory can have on public speakers. Early in my career working with CEOs and entrepreneurs, I noticed that some of their mission-critical presentations would fall flat despite hours of preparation. When I asked one speaker what had happened, he said, "I didn't believe in myself."

That's when I figured out what Zinsser has been teaching military leaders and professional athletes for decades--victory starts in your head.

"Your performance when it matters will always depend on whether you feel totally certain in whatever level of competence you have achieved," Zinsser says.

Achieving First Victory requires that you dedicate yourself to working on your mindset. Zinsser recommends a two-step process for building unshakable self-confidence.

1. Retain and benefit from your successful experiences.

Champion athletes practice under stressful conditions. For example, football teams will often pipe high-decibel stadium-like noise through the loud speakers while an NFL kicker is practicing his field goals. After the kicker has successfully completed dozens, if not hundreds, of field goals in practice, he can retain that experience for the big game. 

The same technique applies to public speaking. I encourage speakers to practice their presentations from start to finish, even if they make a mistake. Keep going. And if they can practice in front of a few people, that's even better. It adds just a little stress to the rehearsal and gives them a little boost of confidence every time they complete a practice round.

2. Release or restructure your less successful experiences.

We all make mistakes or fail to match our expectations from time to time. The secret to peak performance is to "release" those feelings (forgive and forget) or reframe the "failure" into a constructive thought.

For example, Melanie Perkins, the co-founder of Canva, once told me that her first pitch deck for investors did not have the intended result to win funding. Far from considering it a failure, Perkins made note of what investors liked about her idea, which built her confidence, and used their feedback to refine her pitch. It eventually worked, and today Canva is worth $40 billion.

Don't believe that unshakable belief is reserved for a lucky few who are just wired that way. According to Zinsser, confidence is a quality that you can develop just like any other skill--through practice.