How often do you look at your 401(k) or IRA? In times of economic turbulence, there's the tendency to look often at the losses and think the sky is falling. But the sky is only falling if you need that money today. The real danger comes when we beat ourselves up over the losses and sell our holdings -- thereby locking in the losses.

Vanguard founder John Bogle has a radical idea that runs counter to what most people do: In a San Francisco Chronicle article, he suggests that you should never check your retirement funds until the day you retire! Bogle's thinking is that you'll do fine if you're suitably diversified.

Clark has been a long time advocate of diversification. He particularly likes the Total Stock Market Index fund for investing in a broad range of American capitalism. In addition, it's important to put some of your money overseas because that's where capitalism is really ramping up. Beyond stocks, you may also want to have some bonds and possibly up to 5% or 10% of precious metals in your portfolio.