I think it is time for Trump not only to keep characterizing the MSM as purveyors of fake news, but to become sarcastic about it in his tweets.
He could start comments like, "Did you hear the latest fiction from the NYT? They're saying they know what is written in a private memo that they don't have and no one can possibly have seen. And they are running this memo as news! They should win a fiction award!
We need to make fun of their “unnamed sources” who tell lies.