Early in my entrepreneurial career, American Express acquired my first start-up, a company called Competitive Technologies. I remember wondering why a company with seemingly infinite resources would buy my much smaller one. And executives there told me why: there are some aspects of the way start-ups operate that even the world's most established companies can benefit from.

Here's a few ways long-standing and even large companies can behave more like start-ups:

1. Stand for Something

People you know who work for bigger companies are sometimes envious of the sense of belonging that start-up counterparts have. The sense of mission, the excitement. So put it back. Find a cause and rally all your employees around it. Give them a unifying sense of purpose, something they can share and feel part of. After all, if a winning sports team can unify an entire city, then surely you can energize your own employees around winning your Super Bowl in whatever market you're in. Draw that Super Bowl goal on the board, and hold a pep rally to get everyone excited about winning together. When's the last time you held a pep rally at work?

2. Collaborate

Start-ups are "scrappy." But being scrappy doesn't mean doing everything yourself. It means getting things done efficiently; sometimes that means bringing in a partner. Established companies often think they already know everything. Yet Google recently called us at ColorJar to conceptualize, design, and develop new prototypes based on Google technology. Why would a big company like Google, with nearly unlimited brainpower and resources, choose to partner with a small company rather than do the work in-house? Because there's value to bringing in outsiders with fresh ideas, people who won't get bogged down by everything else the organization is doing. If Google can do it, why can't you? Invite a local start-up to work on a project with you. Then stand back and be amazed at your combined power.

3. Stay On The Pulse Of 'What's Next'

You can't do this from inside your conference room. Leave your office and connect with your customers on their turf. Forget everything you know and listen and observe like a child exploring a new planet. But instead of going back and just telling your findings to your co-workers, present what you've learned to an outsider, someone not already molded in the way your company operates. I often get asked by companies to listen to their new ideas precisely because I don't know how their company does things today. An independent observer can often see what you're missing.  You wouldn't proofread your own work.

4. Reward Risk

Not all ideas are good ones. They won't all work. But start-ups are the source of so many breakthroughs and disruptions across industries because their employees are not afraid to try ideas out. Think about the culture at your established company. Are people hesitant to make radical new suggestions? Are managers more worried about upsetting you than taking chances that could catapult the company ahead in the market? Do you reward risk, or just punish failure? You can't have one without the other.

5. Have Fun

In the early Priceline days, I put a sign on my door that said "It is OK to have fun here." Some big companies think that if you're laughing and having a good time at work, you must not be working hard enough. Quite the contrary. Look in the dugout of the baseball team in first place, the one winning all its games. That's where you'll see the pranks and the fun. Humor eases the tension, and employees that love being at work do a much better job. When's the last time you went down the hall and played a little practical joke on an employee? Try it sometime, and watch the smiles and laughter turn into energy and increased production. Start-ups are fun because they're designed that way. Your company can be, too.