The Standard & Poors 500 (500 leading companies in leading industries) and the Wilshire 5000 (publicly traded companies in the United States) are each a list of stocks that represent much of the stock market. Owning the entire basket of these stocks has outperformed the actively managed mutual funds (funds that buy and sell individual stocks based on some investment theory) over long periods.
Moreover, the likelihood that your fund manager will perform better than random has been getting worse. For detailed analysis, you may want to read the article False Discoveries in Mutual Fund Performance: Measuring Luck in Estimated Alphas
“… the proportion of skilled fund [those with a positive alpha, net of trading costs and expenses] managers has diminished rapidly over the past 20 years, while the proportion of unskilled fund managers has increased substantially.”
Therefore, for the bulk of your investment, and until you believe your analysis will be better than those who are competing against you, consider index funds. The largest index funds are provided by Vanguard, and there are many others. Carefully look at the expense ratio. In progress is The Investing Channel’s index fund checklist. Another valuable approach is to invest in the best dividend stocks.