One literary device Shakespeare makes use of in Act I, Scene III is figurative language, such as puns. Since puns twist words, or give more than one meaning to a word, they are a perfect example of using language in a non-literal way, otherwise called using figurative language. We especially see Juliet's Nurse making puns in Act I, Scene 3. For example, when asked how old Juliet is, Nurse makes a pun out of the word "teen" in the lines:
I'll lay fourteen of my teeth--
And yet, to my teen be it spoken, I have but four--
She is not fourteen. (15-17)
What she is literally saying here is that she's so certain that Juliet is thirteen, almost fourteen, that nurse would bet "fourteen of [her] teeth" on it. However, she makes a further joke saying that she actually only has four teeth. The word "teen" is a pun because literally it can be translated to mean sorrow, but it can also refer to Juliet as a teenager. Therefore, what Nurse literally says in line 16 is "to my sorrow be it spoken, I have but four [teeth]," but she can also be saying, "I confess to my teenager [Juliet] that I only have four [teeth]."
A second literary device Shakespeare makes use of in this scene is imagery; he especially uses imagery to characterize Paris. For example, Nurse calls him a "man of wax," referring to a wax statue, meaning that his beauty is statuesque, he is very handsome (80). Both Lady Capulet and Nurse add to his physical description by referring to him as a "flower." Lady Capulet further portrays Paris's beauty when telling Juliet to consider him at the ball that night, saying:
Read o'er the volume of young Paris' face,
And find delight writ there with beauty's pen;
Examine every married lineament,
And see how one another lends content. (85-88)
In saying this, Lady Capulet is telling Juliet to notice how handsome Paris is, to notice how "beauty" has written on his face with her pen and how all of the lines of his face work together well, creating balance and strength. Characterizing Paris as a handsome, desirable man helps us to see later on that marrying Paris really would not have been such a poor decision for Juliet to make.