8. Diversify Your Assests

Try to reduce any company stock you own in your 401(k) to less than 10 percent of your total retirement assets. Just ask employees of Enron, Bear Stearns, Merrill Lynch, and Washington Mutual how smart it was to make big bets on their own stock. Mutual funds and exchange-traded funds (ETFs) are ideal for retirement savings because they own dozens of stocks in their portfolios.

If you're flummoxed by all the investing options in your 401(k), look for a "target retirement" or "life cycle" fund. Then pick the specific portfolio that dovetails with your expected retirement age and you're all set; you will be invested in a mix of stock and bond funds appropriate for your age. You can also invest your Roth IRA in these types of funds; Fidelity, T. Rowe Price, and Vanguard all offer these one-and-done options.

9. Don't Obsess Over Your Home's Value

If you own a house and can afford the mortgage, consider yourself lucky. Try to love your home for what it is: a haven for you and your family, not a path to riches. Unless you bought at the height of the market in a super-popular region that has gone Ice Age–cold, you're going to be fine. And even if you did buy at the peak, if you plan on staying put for five to 10 years, the real estate market will recover with time. But let's be clear: A home is not an investment that will fund your retirement or vacations. The 10 or 20 percent annual gains during the housing boom were temporary insanity. Buy a house you can really afford, and over time it will rise in value. But its main value is as a home. Period.

If you got caught buying into the housing bubble and are now in mortgage trouble, talk to the lender about your options. Don't raid your retirement accounts to keep up with the payments. What happens when the retirement accounts run dry? You still won't be able to cover the mortgage, and you will have lost all your future security.