This morning at the Cannes Lions Advertising Festival in France, Interpublic Group (IPG) recruited Martha Stewart, CNN's (TWX) Soledad O'Brien, and Coca-Cola (KO) SVP Wendy Clark, among other prominent women, to answer that question. My job there? Summarize their insights and share a few of my own.

All in all, there were plenty -- and way beyond the well-worn platitudes. It's worth sharing the three takeaways I talked about in my closing remarks:

1. Get a sponsor. Sylvia Ann Hewlett, the expert on corporate diversity who opened today's program, observed that women are typically way too honest when faced with career opportunities. Indeed, we all know women who have turned down promotions because they're not sure they want the bigger responsibility. Fine to think it -- just don't say it, Hewlett chides. "If you have ambivalence, share it with a mentor rather than your boss," she says. Better yet, get a sponsor -- an advocate inside your organization who has your back and looks for ways to advance you when your foot is off the gas.

2. Get a grip on the talent pipeline. At Coca-Cola, as at most companies, about half the employees bubbling up through the talent pipeline are female -- but too many women eventually leak out. One of the problems, according to Clark (who is a fast-rising star in the marketing group), is senior management's methods of assessing those up-and-comers. Coke identifies its promising talent as "Ready future" or "Ready now" -- but has a poor track record of moving "Ready future" women into the "Ready now" box. This is a problem at many companies, Clark says, adding, "Ready future' is a salve that makes organizations feel good."

3. Get the men on board. "The first thing we have to do is get the men on our side," said Lynn de Souza, chairman and CEO of Lintas Media Group, an IPG unit. De Souza is based in India, where women, she noted, are generally seen as inferior to men. A women's leadership council where she is a member changed its name to "Equal and Opposite" -- a message targeted point-blank at men, who the group often engage. "It's not about diversity; it's about inclusion," de Souza says.

Indeed, the key step may be to make sure that the guys -- still in charge most places - -understand how women view power. For women, power is more about influence than control, more horizontal than ladder-like. And when it comes to building businesses, it's about creating the companies we want to work for.