Tony Saliba discussed the elements of good trading in Market Wizards: Interviews with Top Traders.

Clear thinking, ability to stay focused, and extreme discipline. Discipline is number one: Take a theory and stick with it. But you also have to be open-minded enough to switch tracks if you feel that your theory has been proven wrong. You have to be able to say, “My method worked for this type of market, but we are not in that type of market anymore.”

He continued to discuss trading rules he lived by

Always respect the marketplace. Never take anything for granted. Do your homework. Recap the day. Figure out what you did right and what you did wrong. That is one part of the homework; the other part is projective. What do I want to happen tomorrow? What happens if the opposite occurs? What happens if nothing happens? Think through all the “what-ifs.” Anticipate and plan, rather than react.