Exaggeration: Betty's illness. People immediately start leaping to witchcraft the second one girl in town starts acting a little strange? Once the witch card is thrown, everyone seems to lose all reason.
Incongruity: Consider the entire ill-logic behind the court's system of accusation and confession. If you confess to being a witch, then you are not punished. If you refuse to confess, you are hanged. Incongruity fits well with irony, which I have provided a link to below (several examples of irony are listed).
Reversal: Consider Abby's behavior of Mary Warren. When Mary was attempting to discredit Abby, Abby went so far as to pretend Mary was an evil bird coming to tear her eyes out. But as soon as Mary stops, Abby's "affliction" goes away. Mary also had a reversal there; she started out determined to tell the truth, then backs down, and lies again.
Parody: All of the girls are mimicking each other when it comes to enacting the symptoms of being attacked by witches; they play off of each other so much that when alone, Mary can't even imitate what they were doing. Mary briefly parodies Goody Osburn, recounting the testimony Osburn gave in court. And perhaps Tituba parodies the beliefs and attitudes of the Puritan community that she lives in, as she confesses to witchcraft, pledges allegiance to Christ, thus avoiding whipping or hanging.
I hope those ideas help!