I've always realized that I never really need to be aggressive at all. All it requires is that I at no time be concerned with the way others think I should be living my life. ...and that, Sirs and Ma'ams, is how I do it while being polite.
Especially self-honesty. The saddest part is that most will begin to believe their own lies as if they were true and this makes for very distorted thinking and inaccurate memory recall - very challenging in therapy.