Anyone can succeed by doing these 3 things, says Sirius Radio co-founder

Entrepreneurs who are just starting out should brace themselves to hear the word "no" over and over.

"When you start a company, everybody will tell you, 'No, no, no,'" said serial entrepreneur Martine Rothblatt, a founder of Sirius Satellite Radio and biotech firm United Therapeutics.

"You'll hear 99 — maybe 999 — no's before you get to a yes," she said.

Rothblatt certainly knows a thing or two about overcoming obstacles. After co-founding Sirius in 1990, she made a career 180 when she learned that her youngest daughter had developed a fatal illness called pulmonary hypertension, which lacked approved medicines to treat it.

Despite having taken her last biology and chemistry classes years earlier in high school, she doubled down on finding a cure and founded United Therapeutics in 1996.

"When you're motivated to cure your daughter, you're going to do everything," she said. "I just went to the library to become competent enough to find a molecule that would at least halt the progression of her disease."

Martine Rothblatt, CEO, United Therapeutics
Adam Jeffery | CNBC
Martine Rothblatt, CEO, United Therapeutics

This led to an FDA-approved drug that is now used by thousands of people, and the company has subsequently been able to get other medicines approved.

(Rothblatt was also a pioneer in her personal life, having undergone sex reassignment surgery in 1994.)

While Rothblatt does not think that her success in two very different fields came from a "simple formula," she does think there are a few things that can bring success to almost anyone.

"You've got to be able to question authority and say, 'Why can't this succeed? Why can't my product work?'" she said.

You also have to be persistent, she said, because "there will be so many times that you just feel like giving up."

Having passion matters, too.

"You've got to work on something that you have a passion for," Rothblatt said. "You've got to feel that the success of your project is even more important than your own life."