What is the elusive quality that separates the successful entrepreneur from the dud?

It's not persistence, because even determined people fail.

It's not vision, because visionaries sometimes lose sight of their goals.

It's not money, because well-capitalized businesses can go under.

"It's a state of mind," said Dick Kazan, chairman of Capital Associates, a successful Lakewood, Colo.-based computer leasing company. "If you really believe in yourself, then all things become possible."

Kazan, whose company has leased more than $3 billion worth of computer equipment to Fortune 500 companies, earned enough money to leave the day-to-day responsibilities to colleagues and move back to Los Angeles to pursue other interests.

In addition to volunteering his time to social service organizations, he hosts "The Road to Success," a Sunday afternoon talk show on KABC radio in Los Angeles.

"To really serve your customers, you have to be personally involved," Kazan said.

Personal involvement and attention to detail are the secrets of success for the Bigg Chill bustling yogurt shop in West Los Angeles.

While a franchised yogurt shop across the street remains virtually empty, every day hundreds of regular customers line up for generous servings of the fat-free yogurt and toppings.

The Bigg Chill is owned and operated by Diane Dinow and her son Michael Mendelsohn and daughter Cary Russell.

"Our customers know we care," Russell said. "When you walk in, there aren't three 15-year-olds giggling behind the counter. One of us is always there."

The store is known for its unusual flavors, and about 150 people a day call to ask which eight will be on tap, say the owners, who decided to record a message listing the daily lineup on their answering machine.

Mendelsohn, who concocts most of the 250 flavors, said chocolate, vanilla and peanut butter are solid best-sellers and that Mounds Bar and toasted almond also have been big hits. Customers rave about the generous portions of yogurt and toppings.

With no retail experience, Dinow quit the real estate business, sold her home and bought the yogurt shop three and a half years ago.

"I worked with the former owner for three months, learning how to run the business and order supplies," she said. "When I took over, I changed all the flavors, added fat-free muffins, cookies and a lot of sugar-free, healthier things. Then everything just took off."

In response to customer demand, this month the family is opening a second shop in Studio City, Calif. Although the original store was profitable, Dinow said she was unable to get a Small Business Administration-guaranteed loan because the money was for a new restaurant, which most bankers consider risky. She finally obtained a $100,000 loan from First Citizens Bank in Sherman Oaks, Calif., to finance the second store.

Dean Williams, First Citizens senior vice president, and his yogurt-loving wife visited the store several times to check out the crowd. He was impressed by the huge portions, high quality and happy customers.

While intense family involvement is the Bigg Chill's secret of success, outsourcing helped Ellen Tauscher launch her new business, Child Care Registry, on a national level.

After spending years on Wall Street as an investment banker and stockbroker, Tauscher quit to have a baby. Before her daughter was born, she began interviewing potential nannies.

"I started meeting tax fugitives and 300-pound people with no teeth," said Tauscher, who soon realized it was nearly impossible to fully check out someone's background on her own.

Because she didn't want to start from scratch, Tauscher contracted with an investigative company in Virginia to handle the background checks. Customer calls and requests for information are handled by a telemarketing firm near her home-based office in Danville, Calif.

Tauscher relied on her husband's expertise as chairman and chief executive of Computerland Corp. to help her develop a proprietary software program. The program produces a four-page report detailing where a person has lived for the past seven years, motor vehicle department records, educational records and personal references. Child care providers sign a legal release to be checked out and pay $75 to register with her service. Parents pay $100 to obtain a copy of the report.

"The good people are registering with us right and left," Tauscher said. Since the business began in September, 4,300 people have called for information. (The number is 510-248-4100.)

Who watches Tauscher's 2-year-old daughter while she manages the Child Care Registry?

Two upstanding graduate students share the job.

Jane Applegate is a syndicated columnist. Write to her at P.O. Box 637, Sun Valley, Calif. 91353-0637.