People love a hot story, and the financial markets always oblige. But by the time you hear about it, you've usually already missed out on some of the most significant gains.

Much of the popular appeal of financial television results from the way it treats every day as a significant event. Whether the market finishes up 5 points or down 10 becomes a critical issue in each and every market session. And when certain types of investments heat up, the media promises that you'll be the first to hear about it.

The last to know
In reality, however, by the time most trends hit the financial pages, they're already old news in the investing world. Consider the latest hot market: precious metals. Platinum has hit a series of record highs in the past week, having climbed $600 in just a month to trade above $2,100 per ounce. The metal's performance has reawakened interest in producers like Stillwater Mining (NYSE: SWC) and North American Palladium (AMEX: PAL).

But the fact is that platinum's performance so far in 2008 is just the most recent part of a bull market that started seven years ago, when platinum was trading for just $400 per ounce. Those who invested in the white metal back then have a 400% gain in hand. Even if platinum prices continue to rise, you still wouldn't do nearly as well as those first investors -- the price would have to move up another $2,000 to double your money, while the same rise would turn their investment into a 10-bagger.

Buy while it's warming up
That doesn't mean you have to get in on the ground floor of every investment you make. For instance, those who've searched for a bottom in housing stocks like Toll Brothers (NYSE: TOL) and Pulte Homes (NYSE: PHM) have been frustrated for several years now, as every bounce for shares has been followed by a trip back down. Insisting on buying at the bottom will mean you'll miss out on many opportunities just because you were a little late to the game.

There's a big difference, however, between aiming for the perfect bottom and waiting for a huge move before making an investment. Take another example: the red-hot agricultural market. Increasing standards of living in populous countries like China and India, combined with competition for grains from production of biofuels like ethanol, have sent grain prices soaring. Shareholders in companies like Monsanto (NYSE: MON) and Archer Daniels Midland (NYSE: ADM) have earned strong gains as a result. Yet while these trends may continue, the monster profits have already been made by those who got in early.

Release your inner skeptic
When you see a hot news item, ask yourself why it's running now. If someone touts gold at $900 per ounce, were they even more enthusiastic when it was trading below $300? When an analyst suggests Google (Nasdaq: GOOG) stock at $500, were they just as excited in 2006, when it was trading for a third less?

It's easy to let media hype convince you that you have to own an investment right now. But before you let emotion rule over your common sense, take a moment to consider whether there's any profit left. There are much bigger gains to be made from discovering the next big opportunity before it makes the front pages than by trying to eke out the last few percent from a bull market that's already happened.

One way to avoid the hype is to set up a solid portfolio of mutual funds as your core investments. Our Champion Funds newsletter can help you put together a winning plan, with funds that seek out the next hot investment ideas before others discover them. Check it out now with a free 30-day trial.

Fool contributor Dan Caplinger has learned the hard way about hot investments. He owns some platinum coins he picked up a while back, but he doesn't own shares of the companies mentioned in this article. The Fool's disclosure policy won't just flirt with you.