Hubris is the excessive pride of the tragic hero. In this play, Willy Loman's hubris is his refusal to find a better job.
Peripeteia is the point in the play in which the fortune of the tragic hero is reversed. In this play, Willy Loman experiences peripeteia when he is fired from his job by Howard.
I can't just throw myself on my sons! Whaddya think I am? A fruit???
Anagnorisis is the point in the play where the tragic hero experiences a realization about himself and strives to make it right. One example is when Willy decides to plant seeds in his back yard, because he feels dissatisfied with what he has done for his family.
The catharsis was the moment of emotional release in the tragedy. In this play, the moment of catharsis occurs when Willy kills himself.