Just look at Andy Miller.

In 2009, long before mobile apps had become a staple of modern-day-life, Miller saw a business opportunity. He could tell that apps were on the verge of becoming a booming industry. That’s why he developed CardStar—a mobile app that consolidates all of your membership and rewards cards.

It was an immediate success. In just three years, CardStar gained more than two million users. In 2012, to help expand CardStar’s offerings and customer base, Miller sold the company to Constant Contact, a leading provider of online marketing tools for small businesses.

“Being able to put the incredible resources of a larger company like Constant Contact behind CardStar has been great,” said Miller. “Not only does our user base continue to grow—CardStar currently has more than three million users—but we’re also introducing more ways to help merchants through the app.”

Today, CardStar represents 240,000 venues across more than 250 brands. They’ve also added many new features, including location-based services, saved offers, shopping lists, card sharing, notes, and more.

As part of the acquisition, Miller accepted a position as Constant Contact’s director of mobile products. He quickly worked up the ranks to become Chief Innovation Architect, where he oversees the organization’s Small Business Innovation Program, a new accelerator that helps scale entrepreneurs and startups developing solutions for small businesses.

There’s no question Miller is a successful innovator. But how did he get there?

First, you need the internal drive and passion—it’s just as important as understanding the business concepts, he explained.“You can’t teach someone to be an entrepreneur. You have to have it in you,” he said.

Second, you need the education to back it up. When Miller launched and sold his first venture—RetirementSuite.com— he didn’t have the business acumen he has today. “I realized that there was still so much I needed to learn in order to successfully launch another business,” Miller said.

And he wanted to learn from people who had gone through the struggles and joys of startup life. That’s when he found Suffolk University’s Sawyer Business School—known for its practical, hands-on approach to learning.

The most crucial part of his graduate business education was the collaborative focus. Working in teams, he learned how to delegate and take advantage of the group’s strengths, all of which have proven to be essential skills in his everyday work life.

“The team-based projects were incredibly valuable to me, as I was able to bounce ideas off a lot of people with vastly different backgrounds and skill sets. Being able to work with a marketer, a product, designer, and someone with a history in finance on the same project helped me look at problems from many different angles. This is a skill I use constantly today.”

In fact, the number-one piece of advice he gives to aspiring entrepreneurs is—“you can’t do it alone.”

“You can’t underestimate the importance of having a good team around you. They must share your passion, energy, and devotion towards the product you have created and towards making it succeed,” he said.

Finding teammates with mental toughness is also key. “There will be serious up and downs ahead of you. The people who can handle both and can keep going with equal fervor are the ones you want to keep around,” Miller said.