What are some literary devices in act 3, scene 5, lines 204-242?

In the beginning of this section of the text Juliet uses apostrophe to appeal to heaven to ask for some pity for her situation. Apostrophe is a literary device in which the speaker addresses someone or something that is not actually present. Apostrophe could be directed to someone or something that is real but not currently present, or to an abstract concept like death or love. In this case Juliet appeals to the sky/heaven/God when she cries out "Is there no pity sitting in the clouds / That sees into the bottom of my grief?—" (3.5.208-209) Although her mother and her nurse are in the room, Juliet is not speaking to either of them in these particular lines.
There is also a reasonable amount of alliteration used in this scene, especially to emphasize Juliet's distress. The repeated "s" sound in "Alack, alack, that heaven should practice stratagems / Upon so soft a subject as myself" (3.5.221-222) emphasizes Juliet's vulnerable and "soft" state. Additionally, when the Nurse offers her advice to Juliet, Juliet claims that this advice has "comforted me marvelous much" (3.5.243). The repeated "m" sound draws attention to this line. The audience knows that Juliet is not actually comforted at all, but Juliet's speech here does emphasize this line to fool the Nurse so that she will not be suspicious of Juliet's next plan.

In this scene, Juliet has been angrily ordered by her father to marry Paris, even though she is secretly married to the now banished Romeo. When she discusses this with her Nurse, who knows of the secret marriage, the Nurse pragmatically advises bigamy. She uses the literary devices of imagery and metaphor to compare Romeo unfavorably to Paris. First she says:

Romeo’s a dishclout to him.

In other words, Romeo is nothing but a dishcloth compared to Paris, who, we can assume, is made of finer stuff. "Dishclout" is an image, something we can imagine in our mind using the five senses. We can see and feel a rough dishcloth and imagine that Paris is made of finer stuff. Likening Romeo to a dishcloth is also metaphor, a comparison between two unlike things that does not use like or as. The Nurse continues to use metaphor and imagery to compare Paris to an eagle:

An eagle, madam,
Hath not so green, so quick, so fair an eye
As Paris hath

Juliet is speaking with irony, or saying the opposite of what she means, when she says to the Nurse:

Well, thou hast comforted me marvelous much.

We know this is ironic, because as soon as the Nurse is gone, Juliet uses a soliloquy, the literary device of a character speaking his or her thoughts aloud, to say that she will never trust the "fiend" (another metaphor, comparing the Nurse to a demon) again.