The professional fund manager will be surrounded by knowledge of the type above, and others that will confront them with such knowledge. An active trader will also build a lot of similar knowledge. It is necessary to form strategies that helps you to avoid the pitfalls of that knowledge.
These strategies not only need to tell you when to buy or sell, but also what to buy or sell. Many people are focusing on when, but are you aware that the "what" is also a very important question for a strategy to define?
There are many strategies that work in the market, and if they fit your personality, you can use them for profitable trading. But if you do not follow those strategies, the combination of those strategies combined with your cherry-picking may well turn your trades into losing trades. There are many different paths to use to cross to the profitable side, but they are all narrow and will break if you burden them with unnecessary cargo.