Australian-born Brian Smith was confident he had an idea worth a fortune when he decided to bring sheepskin boots to America in 1978. 

And he was right--today, Ugg generates more than a billion dollars in sales each year. But that success didn't come overnight, he said in an onstage address at Inc.'s Fast Growth Tour in San Francisco this week. When he first took $500 worth of Ugg boot prototypes to California surf shops, the owners didn't understand why warm boots would make sense for a beach market. It took years of selling boots from the back of a van in parking lots by the beach--as well as a lot of mistakes and pivots--for Smith to eventually establish Ugg as the ruler of sheepskin footwear.

Besides the perseverance that it took, Smith said he attributes his success to a handful of mantras. Here are three he lives by.

1. Feast upon uncertainty.

When Smith was a recent graduate embarking upon his entrepreneurial career in the '70s, he wanted an idea that would be immediately successful. But, he noted in his remarks, that that's not possible--and you need to be patient and bask in the uncertainty instead. He compared coming up with an idea to having a child: "You can't give birth to adults."  Let the idea go through its uncertainty-ridden infancy, youth, and teenage years first before it can finally mature into a success.

2. Fatten upon disappointment. 

Let the lessons learned from failure inform and improve your decisions in the future. This is what Smith did, when his original advertising for Ugg was failing. The company's marketing campaigns, featuring models wearing Ugg boots, weren't seeing results. Smith heard California surfers talking about how fake the campaigns felt, since the models most likely didn't surf themselves. "Instantly, I knew I was sending the wrong message to my target market," he reflected. Sales improved once he switched to campaigns that showcased real surfers. "The emotional pull that I learned in this instance, I used for the rest of my career," he said.

3. Invigorate in the presence of difficulties.

When Smith had to give investors a piece of the company as it grew, he went into a depression. "I couldn't get out of the house. I could barely talk," he said of that time. But when his new role at Ugg cleared up tedious responsibilities that solo owners typically have to take on, he realized he was happier in the end. "Nearly always, your biggest disappointments will become your biggest blessings," he said.