Doubling your money -- or a "two-bagger" in investing lingo -- is a popular aspiration of investors worldwide. I fondly remember my first double, EMC, and I'm always looking to repeat the experience. The number is seductive, but elusive. So just how do you actually snag one?

The key is to buy shares of companies with above-average business potential and then hold them for as long as possible (ideally forever). When you do that, performance tends to take care of itself -- just take a look at the track records of master investors such as Warren Buffett, James Gipson, and Fred Olstein.

Five years: Solid stories, proven concepts
In a normal market environment, five years is a reasonable timeframe for a double -- requiring a bit less than 15% annual appreciation, excluding dividends. While that's certainly better than average performance in most markets, there are almost always large, high-quality stocks that achieve this level over a number of years.

Looking back over the past five years, it seems that you didn't have to take any tremendous risks to get your double. Stocks such as E.ON, Best Buy (NYSE:BBY), and Archer-Daniels-Midland (NYSE:ADM) all would have fit the bill. And that's no mean feat -- anybody who's been investing for the past five years knows there were some treacherous times along the way.

But here's the part that I find really interesting -- the companies mentioned were already "winners" five years ago. What's more, every single one of these companies was already a large and well-known player in its niche too. It's as easy as one, two, three -- solid companies, proven concepts, strong management teams -- and then you've got your double.

Three years: Emerging excellence, growth industries
To achieve a double in 36 months requires three straight years of 26% appreciation. At this level, you're no longer talking about solid stock-picking; consistent 26% appreciation annually would place you among the master investors. Nevertheless, three-year doubles are possible without exceptional risk.

Companies such as PetroChina (NYSE:PTR), BHP Billiton (NYSE:BHP), and Enersis would have all delivered 100% performance or better, had you bought them in April 2003. There are some common traits here -- resource stocks have become quite popular in the past couple years, and so too have the stocks of foreign utilities and Latin American stocks.

So if you're looking for the next three-year winner, you'd fare well to find solidly run companies with good revenue performance operating in a neutral-to-favorable industry environment. Fool co-founder Tom Gardner believes that health care is one of the next great growth industries, and he has identified a number of companies to help Stock Advisor subscribers profit from the trend, including his most recent recommendation. These recommendations have helped Tom beat the market by nearly 50 percentage points since 2002.

One year: Lightning in a bottle
Guaranteed one-year doubles are the stuff of investors' dreams (and fraudulent newsletter promotions). If you start with $1,000 and double it for 10 straight years (somehow managing not to pay taxes along the way), you'll end up with more than $1 million. This is not a sane expectation, certainly not for a rational investor.

Though it's an unrealistic target, it is a target that some stocks will achieve. Over the past year, you could have doubled your money in stocks as varied as ABB (NYSE:ABB) and Peabody Energy (NYSE:BTU). A large power/automation turnaround story and a huge coal company don't have a great deal in common -- aside from greatly improved recent financial results and broad recognition of that fact from the market at large.

How, then, do you go about stalking the one-year double? If we're talking about real companies and real stocks (in other words, not penny stocks), we're pretty much talking about catching lightning in a bottle: a timely sector, a biotech success, or an incredible turnaround.

At Stock Advisor, Fool co-founder David Gardner bottled lightning when he recommended Palm in April 2005. David saw a wide market opportunity and a company poised to crush its competition, and the stock is up more than 100% since then.

A holistic approach to doubles
Although I'd love for every stock I purchase to quickly double, focusing on single-stock doubles is really missing the forest for the trees. I'd much rather build a solid portfolio of proven companies and superior management that helps me achieve meaningful long-term returns. I even accept the fact that some stocks I pick will -- gulp -- lose money. After all, at any time in your portfolio, some stocks will be rising and others will be falling. But as long as you stick to companies with proven track records, you should survive short-term volatility -- and profit in the end.

This is precisely what David and Tom are helping subscribers do at Motley Fool Stock Advisor. The brothers' more than 80 recommendations are beating the market by some 40 percentage points, and they expect to do even better three and five years out.

Remember that while stalking the double is a worthwhile pursuit, you must keep it within the context of disciplined stock selection and portfolio construction. Investors who lose sight of that risk turning themselves into investing Ahabs forever in search of their Moby Dick -- and we know Ahab fared. Go forth and find doubles, my fellow Fools, but make sure you don't end up harpooning your foot in the process.

Information provided by Capital IQ was invaluable in the writing of this column.

This article was originally published Nov. 8, 2005. It has been updated.

Fool contributor Stephen Simpson owns shares of PetroChina but has no financial interest in any other stocks mentioned. Stephen is the editor of The Motley Fool's new international stock report, Around the World in 80 Minutes , available free with a subscription to Stock Advisor.Best Buy is a Stock Advisor recommendation. The Motley Fool has a full disclosure policy.