Mary Magray, 59 Editor and university lecturer Madison, Wisconsin
"I started investing at the start of the tech and Internet boom. I watched my accounts double, triple and then quadruple in four years--and then all go down again. My problem was getting myself to sell when the going was good. The greed factor was really strong in me. I could have made a lot more if I sold some when stock prices were high." My fix: "I don't think it's a good idea to try to time the market. It's worth getting outside of the irrational part of your investing. Now I regularly sell a certain amount of my winning funds. I don't worry about the ups and downs anymore. When the market has been up for a long time, I take some profits."