In five years, St. Louis native David Choi went from having $18,000 in his bank account to running a $4.5 million Korean-Mexican fast-casual-food chain with four restaurants and a food truck enterprise. Here’s how he did it.

1. Navigate the humble beginnings.

“I started Seoul Taco at the peak of the recession because I didn’t want to work three minimum wage jobs 100 hours a week. I sold my car, cashed out my bank account and found someone selling a food truck in Philadelphia for $40,000. I had $18,000. He sold it anyway because his wife would kill him if he didn’t get that thing out of the driveway. I drove back to St. Louis and went to a chiropractor the next day because it gave me excruciating back pain.

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2. Sell what you know.

“I was familiar with Korean food from cooking with my mom and grandma, and I started making their recipes in a taco for my family. They thought it was weird, but my brother and two friends didn’t. They helped me raise $22,000. The first day we had a line of 40 people and ran out of food. I realized I had to rely on my experience from my teen years -- working at a pizza shop, sandwich shop, coffee shop, Chinese restaurant -- and replicate dishes at a rapid pace.

3. Improvise!

“Starting as a food truck has made us stronger as a brick-and-mortar restaurant because of the improvisation we had to do every day with the truck, from navigating weather to running out of propane gas. It helped us beta test our proof of concept, and since we had minimal overhead, I recouped my initial investment within a few months.”

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4. Grow wisely.

“When we just had the truck, I could be there every day. Now it’s about finding leadership who can take ownership. The failures have been putting people in management positions out of convenience; just because someone is a great employee doesn’t mean they’re a great manager. We have 100 employees, and everyone starts at entry level so they can learn all aspects of the business. At times we do need all hands on deck.”

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5. Be creative about where you set up shop.

“All four of our brick-and-mortar locations took over spaces of former restaurants, which made it easy to get favorable terms on a lease. And because we were born in a truck, we were able to adapt to any space. From 2013 to 2014, our revenue increased by 52 percent, and from 2014 to 2015 our revenue increased by 153 percent, but we are not resting on that. We want to continue to grow.”