You know you need engaged and motivated employees all working together to reach the same goals. But how do you actually make that happen?

You can learn a lot about the answer from Joe Phelps, founder of the Phelps Agency, one of the largest independent marketing agencies on the West Coast. Phelps has worked with Whole Foods, Panasonic, and Tahiti Tourisme, among others. Its dedicated employees helped the agency get rated among the best places to work in L.A. by the Los Angeles Business Journal 10 years in a row.

How did Phelps do it? With three things that are simple--but not easy.

1. Find a purpose beyond just making money.

"Let's have our biggest quarter ever!" might motivate employees on a short-term basis, but if you want sustained engagement, you'll need something with deeper meaning. The purpose of marketing is to get people to buy things--not an inspiring cause in itself--so Phelps decided to give his endeavor more of a purpose.

He began with the goal of selling the most musical instruments of any agency. That was a very motivating goal--so much so that the agency achieved its objective within a few years. Another early client was a children's hospital, and that got Phelps thinking about larger meaning. "You feel better when you're working for something that makes the world a better place," he says.

And so, without really planning to do it, Phelps created the agency's mission statement, which still drives its work today: We're here at Phelps to do great work for deserving clients, in a healthy working environment, to realize our clients' goals and our potentials.

2. Give employees a say.

A mission statement only works if a) you walk the talk, and b) you let employees help decide how to carry it out. Not every Phelps client is on a par with a children's hospital, but all provide products or services that make the world better in some way, or at least not worse.

Controversy arose within the agency when an e-cigarette company came calling. It would have been a lucrative client. Phelps brought the question to a company meeting. "The room became polarized," he says. "A lot of people said, 'This is a nicotine delivery system. It's not good.' Other people said, 'This is cleaner than smoking. It is good.'" Phelps decided to pass. "I don't want to have a client where the whole team is not proud," he says.

3. Make sure everyone gets the memo.

The agency has grown over the years to 95 employees, some of whom arrived by acquisition. Phelps wanted to make sure that everyone was aware of and in sync with the agency's mission. So rather than just hanging the mission statement on the wall, Phelps started printing it on each employee's business cards. Not only that, but before an employee gets those business cards, he or she must be able to recite the mission statement word for word.

How does his staff feel about that? Phelps got a clue at a holiday party at his home some years ago when his employees called him to the piano, and then the entire agency (about 40 people at the time) recited the mission statement to him together. "It's a wooden house, and it just vibrated with all those people saying it in unison," Phelps says.

It was one of the best presents he's ever received. "It didn't dawn on me then, but in the next day or so I realized, it's not just my mission statement," he says. "Now we have a group of people aligned toward the same objective with the same values. And that's where the power comes from."