(a) Will this company be in business for next 10 years?
(b) Will this company keep on generating money over next 10 years and will keep on doing so further?
2. If the answer to above two queries is positive than one can buy the stock.
3. Alternatively one can on the shorter time frame invest seeing the sales, profits, growth in sales and profits, number of years it will take to get back the profits, futuristic problems for the company, real worth of assets and its paying dividend etc. Thus one will see that one need to scan a lot before investing for long term whereas for the longer time frame one need to answer two questions as enumerated in para 1.
4. Befor investing always make a plan, develop your startegy and stick to it, no over exposure in one stock, be patient and one can say that be slow and steady, understand a company, know risks of investing in stock market and avoid over exuberance in bull run and panic in bearish market.