Make sure your portfolio is adequately diversified, so that if one stock goes down, the loss can be offset by other investments that do well. To be adequately diversified, your club should own at least 13 stocks, and the stocks should be in different industries. But after eighteen months to two years, you should reach this milestone. And once you do, you should make sure you maintain this level of diversification. Hold onto your stocks for the long term.
Most investors buy and sell stocks far too often, and lose a lot of money as a result.
Every time you buy or sell a stock you pay a brokerage commission. Even worse, when it comes time to do your taxes, you have to calculate profits on stocks you've sold and pay taxes on these profits. Selling stocks can be very expensive, and can cost hundreds of thousands, even millions, of dollars over the course of a lifetime. If you simply sell your stocks less often you can save a lot of money in brokerage expenses and taxes. Many companies sell software packages that do portfolio accounting.