When Doug Mellinger started his New York City - based software business, PRT Group Inc., he didn't let fear of rejection stop him from cold-calling the top executives in America for guidance. "I was a bulldog who wouldn't go away. I was so determined to get these guys to help me," he says. Mellinger used his experience as the cofounder of an association for collegiate entrepreneurs as a starting point and then asked for advice about his start-up."Very senior people get bombarded all day by people wanting to sell them something," he reasons. "They don't get hit up by people who just want advice."

Of the 40 or so executives he called, 15 agreed to meet with him for half an hour. Then he networked through seasoned executives like the chairman of a multibillion-dollar company whom he'd met briefly through his entrepreneurial group. Mellinger asked people he admired to be his mentors and sit on either his board of directors or his advisory board. His tenacity has been rewarded: PRT's boards have included the chief information officers of several Fortune 1,000 companies. What's more, Mellinger's advisors give him and members of his management team regular homework assignments and send them to leadership seminars. "There's a lot to be said for gray hairs," says Mellinger.