Many people rush into the stock market with preconceived ideas of which the best stock is. This is deceptive as some stocks with potential to grow are not obvious as the case of Microsoft in the late 90s shows. There is no foolproof formula per se. Factors beyond the companies control can result in huge plunges. The quantitative data given by companies is not qualitative and you can't measure such things as a companies' reputation. Hype and emotions in the stock market can create upheavals at short notice.