This is the best answer. You have to know the factors influencing the market. If you are strong in at least some subjets you can spot the opportunities. If you

This is the best answer. You have to know the factors influencing the market. If you are strong in at least some subjets you can spot the opportunities. If you know about economy, you could benefit when the economy is growing and it could benefit almost all companies. If you know economy is weak, you can short, just as an example. Other factors like market, management, managers, consumer behavior, govt policies, foreiegn policy, technology, raw material, rent, trading laws, stock exchanges, accounting etc. will help. Read business magazines and dailies but dont believe everything. But whatever you do, there is chance of failure. So if you are in market read Fooled by randomness and Black Swan. Investing rules from the masters say there is really no rules. You can be daytrader, long-term investor, options and futures, stock picker, index trader, etc. Actually, each style suits personality.