A cynic once said that the world was run by those who showed up. There is much truth to that. You must never stop learning. I'll bet some of the parents here think we finally settled on six. It will never be appropriate to solve tomorrow's problems with yesterday's knowledge, if for no other reason than that we will be dealing with tomorrow's people.
Good judgement is beyond value.
That calls for the exercise of that elusive quality called judgment, and I believe all of us have it, and too few use it consistently. Honest self-confidence, respectfully employed, is essential to good personal relationships. Contemporary advice is to both walk the walk and talk the talk, or perhaps to avoid a poor self-image. Under any terminology, it means to me that you must apply your skills and talents in an honest and straightforward manner, so that you maintain your own self-respect and rely on it without reservations. When someone treats you as if they expect the very worst of you, you can be fairly sure that that is the behavior you will see from them sooner or later.