What are some of the literary devices in Act I?

Romeo and Juliet is a 16th century tragedy by the English playwright William Shakespeare.
Shakespeare makes liberal use of literary devices throughout the play, and—in Act I—we see a number of examples of metaphor and simile, specifically. For example, in the second scene of act one, Benvolio—addressing Romeo—describes Rosaline's beauty as that of a crow, in comparison to the beauty of other women.

Compare her face with some that I shall show,And I will make thee think thy swan a crow.

In the next scene, the nurse invokes a metaphor with the description:

A bump as big as a young cockerel's stone

The fourth scene of the play finds Benvolio using a simile as they discuss the upcoming feast:

Scaring the ladies like a crow-keeper

In addition to liberal use of metaphor and simile, other literary devices used in Act I of Romeo and Juliet include oxymoron (as in scene 1 when Romeo cries out "O brawling love! O loving hate!"), pun, irony, and allusion.
http://shakespeare.mit.edu/romeo_juliet/full.html