Thomas Jefferson, Mark Twain, Buffalo Bill Cody. What do these gentlemen have in common?

Well, yes, they're all famous Americans, but that's not quite what I had in mind. How about I add Dorothy Hamill, Michael Jackson, and Mike Tyson to the list?

What these people have in common, according to a recent New York Times article, is that despite being quite wealthy at one point, they all had brushes with bankruptcy. How could such a thing happen? It's because they were spendthrifts who failed to set anything aside for a rainy day or retirement.

While many of us think that life would be so much easier if only we could get a break by singing on "American Idol" or winning the lottery, that's not the case. It simply does not matter how much you have if you fail to be smart with your money.

Respect every dollar
One key is to spend less than you make. Tough to do, particularly when your neighbor just bought a plasma television and you are green with envy. But if your neighbor is paying interest on that purchase, that television may end up costing a lot more than he realizes. And that's one way to dig yourself deep into debt.

Unfortunately, it takes discipline to deny yourself a plush lifestyle. As former boxing champion George Foreman told The Times, "A lot of people just don't grow up. I mean, 65-year-old men. They just don't grow up. They don't understand that money does not grow on a tree and that you've got to respect every dollar."

But just think about this the next time you reach for your credit card: Is this purchase worth it if it's going to stop me from becoming a millionaire?

Make those dollars work
Seriously, you can be a millionaire if you put the right plan in place. And while it starts with saving your dollars, the next step is to start those dollars growing. Dr. Jeremy Siegel, among others, has shown that the best way to make this happen is to invest in the stock market for the long term. That's because, over long time periods, equities outperform other asset classes such as gold, bonds, and real estate. Yes, even real estate.

The quick way to wealth is to identify a monster performer like TDAmeritrade (NASDAQ:AMTD) before its monster performance. That stock is up more than 35% per year over the past five years. And if you start finding stocks like that on a regular basis, even a small amount of investing is worth it. If you had bought only $1,000 worth of Ameritrade just five years ago, you would have $4,600 today.

Of course, if you're not a master investor, you probably can't count on 35% annual returns for any length of time. But that's OK. Just try this: Pledge to set aside just $167 a month -- about the price of two restaurant dinners for two. Invest that $2,000 each year in a low-cost index fund such as SPDRs (AMEX:SPY) or Vanguard Total Stock Market (AMEX:VTI). These highly liquid exchange-traded funds own stakes in market giants such as PepsiCo (NYSE:PEP), US Bancorp (NYSE:USB), and even Google (NASDAQ:GOOG), and they should approximate the market's historical 10% annual return going forward.

Fool's final word
I know, not as exciting as winning the lottery, but it works. And more important, you can do it. And if you do, you should end up with more than $200,000 in 25 years. Of course, if you increase either your savings rate or your rate of return, you will do better. You'll do best if you do both.

Let's say, for example, that you double your annual savings to $4,000 and earn a modestly better 15.5% annual return. Then, my friend, you will be a millionaire.

As it so happens, that 15% annual return is what Fool co-founders David and Tom Gardner look to approximate for members of their Motley Fool Stock Advisor investing service. (And to date, according to industry watchdog Mark Hulbert, they're doing even better -- posting 22.8% annual returns.) So if you have the saving part down, and you're looking to add a little kick to your return on investment, consider taking a look at our stock picks and everything else we have to offer at Stock Advisor, free for 30 days. Just click here for more information.

Fool contributor Jim Mueller does his singing with a community choir and has no dreams of getting on "American Idol." US Bancorp is an Income Investor recommendation. The Motley Fool'sdisclosure policyis loud and clear.