Once you make the decision to contribute to your 401(k) plan, you'll need to decide how to invest your money. Your 401(k) plan will give you options to select from—a variety of mutual funds that have different degrees of risk and return associated with them. When coming up with an investment strategy, remember to diversify. See the section Managing Your 401(k) Plan Investments for guidance on investing your 401(k) funds.
Once you've chosen your investments, you'll need to monitor them. Take a look at least once a quarter to see how they've done. As your time to retirement grows shorter, you may want to make adjustments. Generally, as you get older, your portfolio should become more conservative. See the section Managing Your Investments.
NOTE: Investing in mutual funds involves risk, including possible loss of principal. No strategy assures success or protects against loss.