What are some techniques used during Juliet's monologue when she found out Romeo killed her cousin in Act 3, scene 2, Romeo and Juliet?

When Juliet learns that Romeo, her husband, has slain Tybalt, her cousin, she personifies her heart and her eyes, saying, "O break, my heart, poor bankrout, break at once! / To prison, eyes; ne'er look on liberty" (3.2.63-64).  She orders her heart, which she now feels to be bankrupt or empty, to break (and, it is implied, kill her), as though her heart could hear her and obey, and she tells her eyes that they'll never be free to look on anything else, that she will keep them imprisoned (again, because she wants to die).  She wishes to give her body back to the earth so that she will not have to feel this pain any longer.

Juliet also uses a number of oxymora (compact paradoxes made up of pairs of conflicting or incongruous words) to describe Romeo and capture her conflicting feelings about the man she loves who is at once her new husband as well as her cousin's murderer.  She calls him a "Beautiful tyrant, fiend angelical! / Dove-feathered raven, wolvish-ravening lamb! [...] / A damned saint, and honorable villain" (3.2.81-85).  This shows how very conflicted she is in her feelings toward Romeo at this point: he seems to her a combination of opposites, like something that looks beautiful and wonderful but is actually terrible and violent.