There's a tradeoff all investors have to make. On one hand, we know that the market can be beaten, as it has been by masters like Warren Buffett and his tutor, Benjamin Graham. On the other hand, it takes a lot of work to research, analyze, value, and buy companies trading at the right prices to potentially beat the market. It can be a full-time job and then some. Worse yet, even if you're eventually proved correct, the old saying attributed to John Maynard Keynes -- "The market can remain irrational longer than you can remain solvent" -- is as true today as it was back then.

With all the effort that it takes to beat the market, many investors are simply better off following an indexing strategy. With a portfolio that consists of Vanguard's Total Stock Market (FUND:VTSMX) fund and its Total Bond Market (FUND:VBMFX) fund, weighted to suit your risk tolerance and time frame, you can come within a tiny expense ratio of matching the market, without much more work than writing periodic investment checks. It's a great, low-impact strategy, and for 90% of current and potential investors, it really is the best way to build wealth over time.

While indexing is great for the vast majority of investors, it simply cannot beat the market's benchmarks over the long haul. If you want to be one of the 10% who has a legitimate chance of doing that, then you have some work to do. It's up to you to determine how much of your time you're willing to put toward the effort. The learning curve can be both steep and expensive to climb on your own, but with the right mentor, you can dramatically streamline the process. If you don't want to make investing your full-time job, the guiding hand of an expert can help get you moving in the right direction.

Getting started
To begin your journey, start by defining your strategy for success. You need a plan, a philosophy, a way of thinking that you can use to build your portfolio. While building that plan, you need to ask yourself the all-important question of "Why?" -- as in, "Why should this strategy work, when so many that have come before it have failed miserably?"

At Motley Fool Inside Value, our strategy is based on the timeless teachings of Graham and Buffett, two of the greatest market-beating investors of all time. Our strategy is simple. We start by determining a business's true worth, regardless of what the stock market says at any given time. Once we've got that pretty well in hand, we compare the company's true worth to what the stock market thinks. If the market thinks the company is worth far less than we do, we buy. Then we wait for the market to catch up to our way of thinking. Just as it has for generations of market-beating investors before us, that simple strategy is still working for us today.

Why follow a strategy?
If you really want to be a successful part-time investor, you need to limit your actions to those things that really help push you closer to your goals. Defining and living by the rules of a strategy takes time and effort, but it is effort well-spent. As Graham said, "In the short run, the market is a voting machine, but in the long run, it is a weighing machine." Without a rational strategy to guide you, you increase your risk of letting negative, short-term voting machine results scare you away from the long-term potential successes as the weighing machine kicks into play.

Take Inside Value selection AutoZone (NYSE:AZO), for example. This leading auto-parts dealer recently sunk below its recommended price as some short-term operating weakness, driven by spiking gasoline prices, meant that more of the company's growth was coming from its share buybacks than from improvement in its operations. Yet because high gasoline prices appear to be with us for a while, folks are starting to realize that it just may be cheaper to keep, repair, and operate an existing car than it would be to buy a newer one, even if the newer one is a fuel-efficient model like the hybrid Toyota Prius. As a result, supported by the solid results and 10% same-store sales growth turned in this most recent quarter by AutoZone's big competitor Advance Auto Parts (NYSE:AAP), the auto-parts business looks to be on the mend.

Short-term worries drove AutoZone's stock below where it was already value-priced. In the longer term, reality helped it recover, to a point where it is now a positive performer for the service. Without the value strategy as your guide, it would have been simple to panic-sell into the decline in an attempt to preserve some of your cash. And that short-term thinking would have meant long-term pain, since early sellers of the stock did not participate in the rebound.

OK, now what?
Once you've decided on your strategy, the next step is to list companies you'd love to own if the price were right. High on my list right now is beverage and snack-food giant PepsiCo (NYSE:PEP). Pepsi is an extremely well-managed business with the No. 1 or No. 2 brands in nearly every category in which it competes. If its shares would just do me the favor of dropping into my buy range, I'd be more than happy to snap some up. Also on my list is newspaper and television juggernaut Tribune (NYSE:TRB). Thanks to a general slowdown in newspaper ads and television advertisers scared away by digital commercial-skippers like TiVo (NASDAQ:TIVO), business is tough for the Tribune media empire. Its stock is starting to reflect that, and if it gets much cheaper, I may soon find myself faced with an offer I simply cannot refuse.

With a solid strategy to guide your investments and a list of companies that you'd be willing to own at the right price, successful investing then becomes the art of waiting. Waiting for a company to fall in price to where it's worth buying. Once you've bought your stake, it's simply a matter of waiting again until its price is so high that the business is no longer worth owning. And waiting is something that anyone can do on a part-time basis.

Are you ready to base your investments on a time-tested strategy that has beaten the market for generations? Are you willing to wait and let the market work for you? If so, then Inside Value might be able to give you the guidance you need to get started. Click here to take a 30-day free trial and find out for yourself if you're cut out to be among the 10% with a legitimate chance to beat the market.

At the time of publication, Fool contributor and Inside Value team member Chuck Saletta had no financial position in any of the companies mentioned in this article. Tivo is a Motley Fool Stock Advisor recommendation, while Vanguard Total Stock Market has been highlighted in Motley Fool Champion Funds. The Fool has adisclosure policy.