'Shark Tank' Investor Says This Is The One Thing You Need To Master Before Going On The Show

Any contestant of ABC's reality pitch show "Shark Tank" can attest to the difficulty of landing a deal.

The contestants need to show the "sharks," or the panel of investors, that they have a great product and strategy that can sell to the market. And then they need to prove their team knows how to execute. On top of that, they need to have a great leader with the desire and passion to succeed.

But according to Robert Herjavec, the CEO of The Herjavec Group and also one of the sharks, so many contestants fail to remember the one thing that's most important and basic to any type of business: its finances.

"Finance is the language of business," Herjavec told Business Insider. "If you don't understand your basic numbers, you're going to fail."

Herjavec says he understands how the contestants could get nervous, because they're under a lot of pressure on the show. But having no idea of the business's finances is usually a sign of an absolute disaster. "The biggest thing is you got to know your numbers," he says.

Aside from knowing the numbers, Herjavec said it's also important for people to invest in themselves. In fact, when asked about the best investment he's ever made in his life, Herjavec proudly said, "investing in myself."

"People always ask me, 'What should I invest in? Where can I find the next Apple?' and I always say, 'Invest in yourself,'" Herjavec said. "The greatest asset you have in your life is yourself. You just got to continue to invest in training, educating, and being in the right place at the right time."