03/18/2013 05:10 pm ET Updated Mar 20, 2013

Dream Big

March is Women's History Month, a good time to reflect on the impact of women in leadership, and on my own career, as I mark an anniversary.

Fifteen years ago, I transferred from KPMG's Dallas office to its San Francisco office to serve a banking client. My Bay Area network consisted of only my client and a handful of people I knew in our local office. But as a woman in business, I knew I needed a broader and deeper support network to succeed. I turned to the Junior League of San Francisco, a nonprofit organization of women committed to promoting voluntarism, developing the potential of women, and improving communities.

Through the Junior League I developed a network of many amazing women and learned new volunteer and leadership skills. The organization, and a number of leadership roles I had in the League, enabled me to begin to establish myself in the Bay Area -- professionally and personally. Moving to San Francisco and joining the Junior League were key steps in my career path that led to my earning the appointment as KPMG San Francisco's first female Managing Partner a decade later.

Yet, in 1998, women were vastly underrepresented at the most senior executive levels in corporate America. For example, the nonprofit organization Catalyst, in its 1998 census of Fortune 500 companies, found that women made up just 11.2 percent of corporate officers and 11.1 percent of the board members in those companies.

Over the past 15 years, corporate America has made more opportunities available to women at the highest levels of their organizations. And I'm proud to say that KPMG has been among the leaders in developing and advancing women.

Since the firm launched the KPMG Network of Women (KNOW) in 2003 with chapters in three cities, KNOW has grown to 60 chapters and 3,000 members, and KPMG has seen a 50 percent increase in the number of women partners. KNOW has launched programs such as Managing Career Life Choices, Moms Who KNOW, and KPMG's Executive Leadership Institute for Women.

Despite these and similar efforts at organizations nationally, when you consider that women account for almost half of the U.S. workforce, the proportion of women in senior positions in American business remains well short of where it should be. In the 2012 Catalyst census data, women made up 14.3 percent of Fortune 500 executive officers and 16.6 percent of the board members, a small improvement over 1998.

So, the question remains: Is there a better way to identify and advance women who have the desire and skill to rise to the opportunity?

Take mentoring to the next level

Women like me have always been told that finding a mentor is a key to advancement, which is true to a large extent. But it takes more than mentoring. While a mentor will help us identify skill and experience gaps and suggest helpful skill training, we should also seek a "sponsor," a person who promotes or advocates on our behalf. Sponsors may do many of the same things mentors do but they go the extra mile -- promoting your visibility, helping you look for opportunities for advancement and develop your own story to achieve success. They are willing to use their own political capital to bring future generations of leaders to the attention of today's leaders.

Mentorship and sponsorship are critical, and can happen at any time during a woman's career. Even talented senior women executives can benefit. My current mentor is a seasoned executive outside my field who is a role model in every category that is important for my career and personal growth. I have many mentors and sponsors (men and women) to thank for believing in me, being honest about areas I needed to improve or build skills and campaigning on my behalf to senior leaders about my potential. This led to promotion to partnership and ultimately my current role leading one of the firm's largest offices!

Pay it forward

For those of us in leadership roles, we know what a privilege and honor it is to serve in these roles. We also know that we have a responsibility to pay it forward by helping others think big and develop and promote the kind of skills necessary for them to achieve their goals. We can do this by becoming mentors, by sponsoring talented women, and at times perhaps just being a friend and sounding board.

Recently, I was invited to speak to the Junior League of San Francisco, where I am now a sustaining member, about my career and how a woman can be successful in business. I told the audience of mostly young career women and working moms that they should dare to dream big, set goals, be proactive in demonstrating their leadership skills to others, and find men and women who can serve as role models and advocates to help make their professional dreams come true -- all the while staying true to who they are personally.

In honor of Women's History Month, as women pursuing careers, we should ask ourselves whether we are doing all we can to dream big and achieve our professional aspirations, and to help others to do the same.