While a lot of people decide to play defensive during a down economy, that isn't the only stance to take. In fact, a weak economy produces a number of opportunities that aren't always there when the economy is strong. While your instincts may be to hole up and wait for fairer days, a more aggressive approach can improve your net worth a whole lot better. Here are a few ways to take advantage in a down economy: Stocks: Warren Buffett's stock-buying strategy has been always been ''Be fearful when others are greedy; be greedy when others are fearful.'' He re-emphasized that stance with an editorial piece in The New York Times last week entitled " Buy American. I Am." Buffett says that due to the fear in the stock market and the attractive prices of U.S. stocks, that's where he's putting his personal money. If you are in the stock market for the long haul, a down stock market is what you want when you are buying. Year to date, the Dow Jones Industrial Average is down more than 30%, and the S&P 500 and the Nasdaq have lost more than 35% each. It's much better to invest in the stock market for your retirement when it's having trouble rather than when it's riding high. The only time you want it riding high is when you are retiring so that you can cash out at the top. Trying to anticipate the bottom is always impossible, so you don't want to wait, but you also don't want to put all your money in at this moment. Instead, begin setting aside an extra amount you can afford to invest on a monthly basis and keep buying with a long-term approach. Your retirement account will thank you for it.