Finance research has shown that managers of actively managed mutual funds or exchange traded funds (ETF), on average, do notoutperform the overall stock market as measured by the S&P 500 index . In some years, more than 80% of fund managers were unable to beat the overall stock market return. The year 2013 is a good example when the S&P 500 yielded nearly 29% return, which was better than the average return on 95% of actively managed stock portfolios with similar risk.These results seem to support informational efficiency of equity markets in U.S.,

what should be my investment strategy so that myaveragelong-runreturns are better than the returnsrealized by more than two-third (75%) of professional money managers of actively traded funds?

If equity markets are informationally efficient and rational to alarger extent, how would I explainthe stock market bubble of 2008 in the presence of efficient markets?