Think. Think for yourself. Ask questions. Question what you know. Ask what you do not know.
Question authority. Question your own authority. Question assumptions. Question the rules. Question what you're told. Pay careful attention to the answers.
Learn the history. Know the context. Decide for yourself. Be prepared to stand your ground. Pay attention to your own mind and your own instinct.
Be prepared to change your mind. Open your mind and your instinct to new possibilities. Comminucate. Act it. Do it. Think again.