Want some insight on building wealth? Just look to Detroit.

Bear with me for a minute, I'm serious. One company I follow closely, for the Fool as well as for my own account, is Ford (NYSE: F), the iconic American automaker. A few years back, Ford famously mortgaged everything it had, including the famous blue oval trademark, in a long-shot attempt to survive until it could return its business to profitability.

If you follow the business news at all, you know how that turned out: very well. Ford's not only solidly profitable now, thanks to a slew of acclaimed new products, but the auto division's cash now exceeds its remaining debt.

How did Ford manage that? For that matter, how did cash-rich technology companies like Cisco Systems (Nasdaq: CSCO), which recently announced that it would pay its first-ever dividend in 2011, or Intel (Nasdaq: INTC), which has more than $20 billion in the bank and has recently been buying back its own stock, accumulate their impressive hoards?

The same way most millionaires do: They spent less than they earned.

Think that's over-simplistic? It's not. Read on.

Want wealth? Here's the way.
Think building wealth is complicated? Think there's some "secret" (or "Secret") to becoming rich? It's not, and there isn't. Spending less than you earn is the key -- the key -- to accumulating wealth.

One of the best insights into America's real wealth-builders is The Millionaire Next Door: The Surprising Secrets of America's Wealthy, the 1996 best-seller by marketing professors William Danko and Thomas Stanley. If you've read it, you know that:

  • Wealthy folks in America are often not the people who look wealthy (because looking wealthy is expensive);
  • A high income isn't the same thing as wealth (and conversely, a modest income doesn't mean you can't become wealthy);
  • One becomes wealthy -- to paraphrase Dr. Stanley -- by being investment-oriented, not consumption-oriented. In other words, by spending less than you earn and by investing the difference wisely.

"Sounds easy but isn't," you say? I hear that. But going from being a spender to being a wealth accumulator is like the proverbial journey of a thousand miles: You do it step by step.

Walking the path to real financial freedom
Robert Brokamp, the Fool's resident retirement guru and lead advisor of the Rule Your Retirement service, has spent a lot of time distilling Danko and Stanley's conclusions into an actionable approach. In fact, much of the newest issue of Rule Your Retirement, available online at 4 p.m. ET today, is devoted to a long look at the lessons ordinary investors can draw from The Millionaire Next Door.

It's true that if you're starting from a place of high debt and high expectations, shifting to a more frugal approach will probably seem daunting. And there's no getting around it -- it will take effort and commitment. But as Dr. Stanley told Robert in a recent interview, the insights in his book have spurred lots of folks to change their financial habits for the better.

It's easier than you might think
Here's one insight that I found particularly telling: According to Danko and Stanley's research, the folks who are good at accumulating wealth are much more likely than others to have short- and long-term financial goals, and on average they spend nearly twice as many hours per month planning their investments.

Given that most folks don't spend much time at all, it's clear that it doesn't take that much time to get a lot better at managing your finances. And the payoff -- whether you're seeking a more lavish retirement, an earlier one, or just the ability to sleep a bit more soundly knowing your finances are under control -- is available to nearly anyone with an income.

Ready to get started? Set aside a little time to have a look at the new issue of Rule Your Retirement. It includes Robert's (excellent) review of the nine most important lessons from The Millionaire Next Door, the interview with Dr. Stanley I mentioned before, and a revealing account of a man who put these lessons to work in his own life and now has a seven-figure net worth as a result.

Rule Your Retirement is a paid service, but (speaking of frugality) you can get full access for 30 days absolutely free with no obligation to purchase -- just click here to get started.