The world's richest person applies the following criteria before he invests in a company.Check out what are they
1. The company should have a good ROE for the past 5-10 years.
2. The debt/equity ratio should be very minimal.
3. The profit margins should be high and increasing over the past 5 years.
4. The company should be a listed entity for last 5+ years.
5. The company should not rely on any singly commodity as its main stream of revenue.
6. Stock price should be 25+% lower than its real value.
The most trickiest part is that how to find the real intrinsic value of a stock and Buffett is the undisputed King in finding out the real value of the company.