Wall Street is littered with commonplace financial advice, but if you want to get your career as an investor off to a smart start, you should consider going against, um, the flow of that traffic. (Just sticking with the metaphor, folks!) To help you step on the gas, consider these three suggestions:

1. Investing isn't an either/or proposition.
For all too many folks, investing is a zero-sum game. Truth is, though, depending on your timeline and tolerance for risk, all of the market's major asset classes -- from the most dynamic growth stocks to more modest fixed-income vehicles -- can play roles in your portfolio. Spreading your bets around, after all, can help take the sting out of market downturns.

For example: Between March 2000 and December 2002, the Russell 1000 Growth benchmark -- an index that counts Qualcomm (NASDAQ:QCOM), Cisco (NASDAQ:CSCO), Medtronic (NYSE:MDT) and Monsanto (NYSE:MON) among its holdings -- fell by some 24.8% on an annualized basis. Meanwhile, the Russell 1000 Value bogey -- which specializes in cheaper big boys such as Wyeth (NYSE:WYE), Home Depot (NYSE:HD), and Chevron (NYSE:CVX) -- shed just 1.7%.

Moral of the story: Don't go whole hog. Tilt in the direction of your investing temperament, but err on the side of a diversified portfolio. Speaking of which ...

2. Funds and stocks can live peacefully -- and profitably -- in the same portfolio.
A solid portfolio begins with top-rate mutual funds. And while you can always opt for an index tracker such as the SPDRs (SPY) exchange-traded fund, remember that, with index picks, you're destined to lose to the market each year by about the amount of your expenses. One solution is to mix index funds with actively managed keepers -- funds that allow you to invest outside your area of expertise and across the market's various cap ranges with managers who have proven over time that they can deliver the goods.

Once your fund portfolio is in place, you'll be in good position to go about the business of researching individual stocks and, if they strike the right profile, investing in them as well.

3. Stay current.
From truisms like "buy low, sell high" to "let your winners run," investment wisdom is plentiful. Executing on those chestnuts is one challenge; staying abreast of the investing landscape is another. Time-tested advice is great in the abstract, after all, but you still have to put it to use in real time.

When it comes to doing that, a helping hand can be, well, helpful. That's particularly true for folks who are just starting out. At the beginning of an investing career, the market can look like an obstacle course, a daunting prospect that may prevent you from even getting started down the path to financial independence.

Not to worry: Smart investing is easier than you think, and we launched Ready-Made Millionaire earlier this year in part to help new investors -- and those playing catch-up -- get up to speed fast. At the center of the service: a compact, real-money portfolio that tilts toward growth with a collection of world-class funds, cherry-picked individual stocks, and one high-octane ETF. With just eight holdings in all, our mission is to crush the market over the next three to five years and beyond with little in the way of muss or fuss.

RMM is set to reopen to new members in just a few short weeks. If you'd like to learn more about a service designed to help you invest for the long haul with a set-and-forget portfolio, just click here. A completely free copy of our 11-Minute Millionaire special report is yours for the taking, too -- just to tide you over until our service reopens. Grab it now.

This article was originally published on June 11, 2007. It has been updated.

Shannon Zimmerman runs point on the Fool's Ready-Made Millionaire service. At the time of publication, he didn't own any of the securities mentioned above. Home Depot is a Motley Fool Inside Value selection. You can check out the Fool's strict disclosure policy by clicking right here.