Kerry O'Brien, 39

CEO, Her Look Enterprises

AGE AT TIME COMPANY WAS FOUNDED: 31

INITIAL INVESTMENT: $3,000

CURRENT NUMBER OF FULL-TIME EMPLOYEES: 15

"I'VE MADE IT BIG" SPLURGE: "Expensive shoes. My ultimate extravagance was a pair of limited-edition Christian Louboutins I bought before an appearance on The View."

O'Brien presides over a Burlington, Vermont-based undergarments empire that includes seamless "Commando" panties and silicone-filled bra inserts ("Takeouts"). Her line is sold in some 1,200 stores, including Neiman Marcus, Nordstrom, and Saks Fifth Avenue.

SECRET #1

Be honest — do you even want your boss's job?

"At 28 years old, I was already very successful — a senior vice president at a big PR firm in New York City. Then September 11th happened, which made me re-evaluate everything. The next day, I quit my job. How did I go from PR to underwear? I love to wear summer dresses, but I'm not a small-chested woman, and I hate wearing strapless bras. I used to MacGyver support using duct tape. It wasn't pretty, but it worked. Then all my girlfriends started coming to me for advice about undergarments. That's when I started toying with the idea of selling my own line."

SECRET #2

If it hasn't been done, doesn't mean it can't be done.

"My first product was Takeouts: The Better Boob Job, silicone inserts for your bra that are sold in Chinese food containers. It was a crazy idea, and people were saying it would never work. So I did a very small amount at the beginning, partly because if it didn't work, I didn't want those takeout containers filling up my closet. But it took on a life of its own. Even today, every time I come up with an idea, the immediate answer is, 'No, it will never work.' But I always say, 'We're going to try it anyway. Prove to me that it can't be done.' I usually won't take no for an answer."

SECRET #3

Have no shame when selling your product.

"I walked in unannounced to just about every boutique and lingerie store between Los Angeles and San Francisco and tried to sell Takeouts to managers. It was an easy product to sell because it was so cute and fun. Still, I was pregnant at the time, and tried to be as fashionable as possible. You have to be able to walk in there and just sell the hell out of it, be a true believer. Because if you're not, no one else is going to be."

SECRET #4

Business decisions shouldn't be big bets.

"I never took big risks. I'm not going to play lottery with my career and my life. I didn't have any outside investors telling me what to do. I never ordered huge quantities of my products. The only thing I took a risk on was the Takeout packaging: I had to have it custom-made. Most people would have bought tens of thousands of units to keep the costs low. But I ordered only a small amount at the beginning, even though I knew that would mean higher costs. It minimized my risk of getting stuck with too much inventory."

SECRET #5

Find seasoned mentors — and use them often.

"In 2003, I moved the business to Vermont, where there's a wealth of talent, a lot of independent spirits and entrepreneurs. I have an informal brain trust here. Every time I need to check something, I call on my marketing friends from Ben & Jerry's, Seventh Generation, and Green Mountain Coffee, all of whom are based in Vermont. We sit around and hash out ideas. They're very accessible to me, and I call them often."

SECRET #6

Even successful entrepreneurs work around the clock.

"I have three kids. Running a business is probably no more difficult than working full time. The difference is that I have flexibility. But the flip side is that I work constantly, making phone calls, reading e-mails whenever I'm not doing the mommy thing. I am always available to my business, night or day. So while I don't have to punch a time clock or tell people when I'm coming and going, I still work all the time."

Kelly Flatley, 31

Founder, Bear Naked Granola

AGE AT TIME COMPANY WAS FOUNDED: 23

INITIAL INVESTMENT: $7,500

FULL-TIME EMPLOYEES WHEN SHE SOLD THE COMPANY IN 2002: 2

"I'VE MADE IT BIG" SPLURGE: "After I sold the company, I went to Paris with my best friend. We stayed at a bed and breakfast on the Left Bank and toured the city on foot, indulging in French wine, cheeses, and crepes along the way."

The million-dollar granola girl from Darien, Connecticut, founded Bear Naked in 2002 with a friend and just $7,500 in seed capital. Five years later, they sold the company to Kellogg's for a reported $60 million.

SECRET #1

Find a job you'd jump out of bed for. (Yes, they exist.)

"I'm a hippie — I'm totally OK with that term — and I love granola. In college, I made my own batches in my dorm room. After I graduated, I worked in marketing at Sports Illustrated Women until it folded in 2002. It was a cool job, but when I sat down to think about what I wanted to do next, I realized it wasn't working at a magazine."

SECRET #2

Ignore your naysayers — there will be many.

"There were so many people who said I was crazy to start something like this. I was extremely young, and I had no business experience. My dad told me to go to Barnes & Noble, get a book on entrepreneurs, and read about the lifestyle changes I'd have to make. He was sure I'd lose my steam. But frankly, I didn't have anything to lose. I was single and living with my parents. It was a very indie operation."

SECRET #3

Ask a million "dumb" questions.

"The first store we sold to said they'd take a case to start, then asked me how many units were in a case. I just looked at the guy and said, 'Well, how many do you want in a case?' Ten minutes later, we were at the register, and he asked me for an invoice. I didn't even know what an invoice was. I said, 'I'm sorry, I'm green. But if you give me a few pointers, I'll run with them.' I wasn't afraid to ask questions."

SECRET #4

The pros don't know it all.

"We packaged Bear Naked in a clear zippered pouch, which was very different from the way cereal boxes are packaged. Early on, the founder of a big grocery chain pulled my partner aside and told him, 'There's a reason why all the cereal companies have been doing it their way all these years. Who wants to see your product?' Normally I'd have said, 'Oh, shit, the expert is telling us we're not doing something right.' But we had conviction and stuck with it. Now we have inspired a new standard for how snack foods are packaged."

SECRET #5

Hire people who know more than you do.

"One of the hardest parts about growing a business is finding people you trust with your baby, who will do the right thing in your absence. We recruited from bigger firms like Campbell's and Pepsi. People like that elevate your business in a way a founder can't."

SECRET #6

Brace yourself for sacrifices.

"For the first two years, there were no paychecks. I worked every single day, baking and doing marketing plans. On weekends we'd go to local triathlons and give out samples at the finish line. I'd be in the office at 10 p.m. on a Friday night thinking, All my friends are at a bar right now, and I'm doing accounting. But we had one shot to make it work, and we were willing to give it everything we had."

Tina Wells, 30

CEO, Buzz Marketing Group

AGE AT TIME COMPANY WAS FOUNDED: 16

INITIAL INVESTMENT: $0 — she founded the company on a quid pro quo basis.

CURRENT NUMBER OF FULL-TIME EMPLOYEES: 7

"I'VE MADE IT BIG" SPLURGE: "My house. I bought it on my own, renovated it, put in a new kitchen, treatments in the dining room, and custom closets. My siblings call it home. I'm really proud of it."

Wells knows what girls want. Her teen-focused market research firm, based in Voorhees, New Jersey, boasts blue-chip clients like Sony BMG, PBS, and American Eagle. She is also the author of the Mackenzie Blue young-adult book series.

SECRET #1

Friends make for cheap labor.

"In high school, I wrote product reviews for a local newspaper. Pretty soon, companies started sending me things directly, asking me to give them feedback. It got to be too much for me to do by myself, so I brought in friends to help, in exchange for free samples. Before long, my friends started telling their friends, and by my senior year of college, I had 250 'buzzSpotters' and was working with Verizon and Chrysler."

SECRET #2

Stir up some controversy.

"I decided that if I was to be taken seriously, I had to get noticed. So I began to publish reports about things nobody was talking about. One was on illegal downloading, which the recording industry wasn't too concerned with at the time. I did a survey with 500 buzzSpotters that found that 99 percent had illegally downloaded music in the previous month. People paid that report serious attention."

SECRET #3

Money is always an issue, even after you've made it.

"My friends and I joke that we've got 'high-class problems' — the same problems we used to have, just multiplied by 100. I started out thinking, Oh, crap, I need $1,500 to pay the rent. Now, 10 years later, I think, Crap, I've got to make a $15,000 payment. Last fall, I had a ton of clients, but then the recession hit. And when big clients stop paying their bills, you feel like you're starting all over again."

SECRET #4

Successful moguls are frugal.

"Business first is a lifestyle. I drive a Nissan Murano. Sometimes people say to me, 'Oh, I'm surprised you don't have a Mercedes.' But you have to have something to work toward. If I had that now, then I'd feel like I'd made it and become complacent. Besides, your employees need to know they're working for someone who isn't buying Louis Vuittons one day, then laying people off the next."

SECRET #5

Reputation is everything.

"I just turned down an offer to star in an episode of Millionaire Matchmaker. It highlights a pretty flashy lifestyle, and to do the show would have been really off-message. There are definitely times I wish I could just chuck my reputation aside and do things for fun. But I've got to preserve my image."

SECRET #6

Be an idea machine.

"A couple of years ago, I was hearing from moms that their daughters were into Gossip Girl, but that it wasn't really age-appropriate. I challenged myself to come up with something that could interest these girls. So I developed the Mackenzie Blue books for HarperCollins. I've shifted from doing research to creating new, innovative products. Five years from now, I'll probably be running my own media company."

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