No matter what you may think of Rudy Giuliani\u2019s accomplishments as mayor of New York City, no one disputes that he stepped up to the challenge of leading the city in the aftermath of Sept. 11. Now on the lecture circuit, Giuliani gave the following leadership tips at a user conference given by software vendor i2 last May 15 in Las Vegas.Have a set of beliefs. "You can\u2019t still be wondering who you are and where you\u2019re going," he says, "because you\u2019ll get confused and go in all kinds of directions. Ronald Reagan was the same Ronald Reagan he was as governor, as president and when he left office. You may not have agreed with him, but you knew what his beliefs were."Become an expert. "When people come to you to ask for advice and information because you know more about a subject than they do, that\u2019s a sign of great leadership," Giuliani says.Be respectful. "People know when you\u2019re talking down to them, and they will not respect you," he says. Be forceful and honest but plain-spoken and respectful, he adds.Discourage yes-men. Create a team that complements your strengths and weaknesses rather than mimicking them, he says.Understand good leaders, not good leadership. "Read biographies of leaders you admire," he says. "That will tell you more about leadership than any leadership book."