“Think long-term, and keep your emotions in check,” says Carrie Schwab Pomerantz, chief strategist of consumer education for Charles Schwab in San Francisco. “The market fluctuates in the short term, but over time a diversified portfolio outperforms any other investment.” She recommends starting with mutual funds, which consist of a variety of stocks, bonds, or both, for less vulnerability to individual stock losses. Buying them through your 401(k) or IRA with regular payroll deductions is a good strategy. Investing this way “smooths out the potential risk of investing a lump sum at a market high,” Schwab Pomerantz says. When comparing funds, “look for low expenses, a sensible strategy, and a solid track record,” says Patrick Dorsey, author of The Five Rules for Successful Stock Investing (Wiley, $17, www.amazon.com). Review your investments three or four times a year. (Are they performing as expected? Have managers changed?) “‘Buy and hold’ doesn’t mean ‘buy and forget,’” Dorsey says. “It means ‘buy and watch.’”