I asked more than 150 high-earning women, "Are you doing this for the money?" The overwhelming response was a definite no. What drove them were passion, recognition, challenge and independence. At the same time, they wanted to be well-compensated, because they felt they were worth it.

But that's not the case with most of us. We instinctively devalue ourselves. Those little voices in our heads insist: "Who do you think you are? No one's going to pay you that much." And I'm convinced self-depreciation goes right to the heart of our financial ruts.

You can easily learn negotiation techniques and assertiveness skills by taking courses or reading books. But the truth is this: If you're going to command more money, you have to truly believe you're worth it. Without that conviction, we lack the confidence to take a strong stand and the certitude to convince others. People always respond to our vibes far more than our words.

Many six-figure women admitted questioning their own value. Yet they didn't let that stop them. These women built their confidence like weightlifters build muscles -- by continually pushing themselves to take a stand, ask for more, demand what they're worth and say no when appropriate despite their trepidation.

Confidence-Building Tips

This advice directly from these women will help you pump up your self-worth along with your net worth:

* Think Big, Then Think Even Bigger: Most of us, especially women, unwittingly limit our earnings by lowering our expectations. Even in studies where women are trained in negotiation strategies, they set their sights lower and end up with less money than men. The idea is to value yourself fairly compared to others in your field or at your level.

* Do Your Research: One of the worst negotiating mistakes people make is picking a random number and then discovering it was way too low. The smarter ones avoid that pitfall by doing their homework. They discover their market value by researching going rates, then asking for more than what's offered to give themselves wiggle room.

* Quantify Your Value: You can counter the tendency to downplay yourself by presenting tangible evidence of what you bring to the table. Maybe you saved your company $X or had an idea that generated so many sales. Keep a file of everything you've done. Don't wait for your review. Go in and ask for work, ask for responsibility, ask for challenge. Let your supervisor know exactly where your sights are set. Taking initiative is an effective means of demonstrating your value and intentions to an organization.

* Practice Daily Affirmations: These positive statements are expressed as if they've already happened. Two examples: "I have the confidence to ask for what I want." "I welcome more money in my life." Write your affirmations down. Post them where you can see them easily. Say them out loud, as often as possible. As one affirmation enthusiast told me, "The more often I hear the words coming out my mouth, the more I internalize it, and the more my psyche knows it's going to happen."

* Challenge Yourself in Areas Outside Your Job: Stretching yourself in any area of life has a ripple effect. If you can't quite get yourself to ask for a raise, try signing up for an art class or running a marathon. Anything that puts you out of your comfort zone builds confidence and self-worth.

* Fake Confidence If Necessary: Asking for top dollar takes a lot of nerve, which most of us won't feel at the time. But that doesn't mean you can't fake it. Even six-figure women have doubted their worth, but they appear undaunted. Acting as if you're confident is a surefire antidote for weak knees, a pounding heart or a deflated ego. Besides, when you act as if you're worth a lot, you'll eventually convince yourself as well as others.

By practicing these tips, you'll begin to notice a shift in how you feel about yourself. Making more money becomes not something you should do, but something you have to do -- because you know in your heart you're worth it.