Martin Zwilling, an angel investor and startup mentor in Phoenix, recalls an event he attended where recently laid-off workers were inquiring about entrepreneurship. When they started going around the room making introductions, he could tell within a few seconds who had a chance at success—and nine out of 10 didn’t.

“They typically said something like, ‘I’ve had this job for 20 years, and I would love to be my own boss, but I don’t know what it takes to do it,’” Zwilling says. “There was only one person who said, ‘I’ve been working on this project on the side for a while, and now that I don’t have a job holding me back anymore, I’m raring to take this opportunity to start my own business.’ Having the right mindset means a lot.”

Making the transition from everyday employee to enterprising business owner doesn’t happen by simply hanging up a shingle. You must also embrace a new way of thinking to thrive in the unpredictable world of startups. Below, we’ve outlined the characteristics you’ll need to adopt—if they’re not already inherent to your personality—to make it on your own.

1. Embrace uncertainty.

All entrepreneurs need to be able to deal with unpredictability on a daily basis, says Jonathan Greechan, co-founder of the Founder Institute, a Silicon Valley-based startup accelerator. “One trait we look for in our applicants is their openness to risk, their ability to learn a new rule and apply it to new problems. Discomfort should become your new normal,” he says.

2. Have a thick skin.

As a business owner, most feedback you get from customers, employees, vendors and investors will be negative. Get used to accepting it and using it to your advantage. “If you’re difficult to be around and argue everything, you’re at one bad end of the spectrum,” Zwilling says. “But if you are a complete pushover who follows all advice, you’re at the opposite end. Good entrepreneurs stand in the middle.”

3. Understand vision vs. mission.

“Your vision is your company’s future, where the market is going, how to meet your customers’ needs,” Greechan says. “Your mission is how you will get there. Your vision needs to be concrete, but your mission may change regularly.” Great entrepreneurs can be detail-oriented yet simultaneously focus on the big things that accelerate their company’s success.

4. Accept failure, again and again.

Realize that you will fail almost daily, and that it’s part of the process and a good learning tool, says Ted Zoller, director of the Center for Entrepreneurial Studies at the University of North Carolina at Chapel Hill’s Kenan-Flagler Business School. “You have to be opportunistic and adaptive. If you find a dead end, either go around it or try something new.”

The best entrepreneurs don’t label their milestones as failures or successes. Instead, they focus on what’s really important: seizing the opportunity. “Whatever you do, act when the opportunity presents itself,” Zoller says. “That’s entrepreneurship defined.”