I actually do try to follow her advice, and I try to never defend myself from obvious slanders or lies. Provided they don't bring any made up proof - then I would have to address that. Usually when people need to accuse someone - they have to bring proof. So, without any proof their words are just invalidated.
On the other hand, I can't follow her second advice and can't ignore that. Because otherwise people actually might believe it if it won't be contested. And the solution to both contest them and not acknowledge their lies is quite simple and elegant: to acknowledge a person as a slanderer and liar. And with that approach my own words are actually proven by the fact of existing slander (accusation in anything without proof).
Then I have ability to invoke that for anything else they say even without getting into detail, without a risk of saying a lie myself (as soon as I just call them a "liar" and not using typical trolling form of "they always lie" - because if I would say that, I will lie myself and lose my honor, since nobody theoretically possibly could say always lies).
I believe such approach to be logically the most efficient.