When Tracy Britt Cool was finishing Harvard Business School, shewrote to Warren Buffett to ask for a job. Less than five yearslater, she's among Buffett's top aides atBerkshireHathaway (BRK/A),where she oversees subsidiaries with more than $4 billion in annualsales and more than 10,000 workers. “She thinks like Iwould,”Buffetttells Noah Buhayar and Laura Colby in thisweek's Bloomberg Businessweek.

Some of the attributes that helped Cool rise aren't easilyimitated. She developed a work ethic growing up on her family'sfarm and was voted most likely to become a billionaire by highschool classmates in Manhattan, Kan. Then she was one of eightstudents from her class at Harvard University accepted directlyinto HBS from the undergraduate program. Here are four of Cool'smore easily adopted habits:

Be a joiner … During her sophomore year atHarvard, Cool led fundraising for the Harvard Undergraduate Womenin Business, served as an executive board member of the Women'sLeadership Conference, and was also a member of Kappa Alpha Theta,according to Buhayar and Colby. One of her college internships wasat 85Broads, a network that promotes women business leaders. LearnCool's remaining three easily adopted habits.