Want to become a tech titan or hedge fund tycoon? Up your chances by dropping out of college or going to Harvard and working at Goldman Sachs. Are billionaires born or made? What are the common attributes among the uber-wealthy? Are there any true secrets of the self-made?

We get these questions a lot, and decided it was time to go beyond the broad answers of smarts, ambition and luck by sorting through our database of wealthy individuals in search of bona fide trends. We analyzed everything from entrepreneurs' parents' professions to where they went to school, their track records in the early stages of their careers and other experiences that may have set them on the path to extreme wealth.

Consistent with the rest of the population, more American billionaires and near-billionaires were born in the fall than in any other season. However, relatively few of them were born in December, historically the month with the eighth-highest birth rate.

Of the 274 self-made tycoons on the Forbes 400, 14 per cent either never started or never completed college. The number of precocious college dropouts is highest among those who forged careers as technology entrepreneurs: Bill Gates of Microsoft, Steve Jobs of Apple, Michael Dell of Dell, Larry Ellison of Oracle and Mark Zuckerberg of Facebook.

Goldman Sachs has attracted a large share of hungry minds that went on to garner 10-figure fortunes. At least 11 current and recent billionaire financiers worked at Goldman or one of it subsidiaries early in their careers, including Edward Lampert, David Tepper, Daniel Och and Leon Cooperman.

Several Forbes 400 members suffered bitter professional setbacks early in their careers that heightened their fear of failure. Pharmaceutical tycoon R.J. Kirk's first venture was a flop--an experience he regrets but appreciates. "Failure early on is a necessary condition for success, though not a sufficient one," he told Forbes in 2007.

Several current and former billionaires rounded out their Yale careers as members of Skull and Bones, the secret society portrayed with enigmatic relish by Hollywood in movies like The Skulls and W. Among those who were inducted: investor Edward Lampert, Blackstone co-founder Stephen Schwarzman, and FedEx founder Frederick Smith.