The line, "Arise fair sun and kill the envious moon," is an example of a metaphor. A metaphor is a comparison of two unalike things where the poet says that one thing is another. Just prior to this line, Romeo says that the balcony off of Juliet's room is the east and Juliet, herself, is the sun, establishing the metaphor. In so saying, Romeo seems to suggest that Juliet has recently (and quickly!) become the most important thing in his life, the thing, in fact, that gives him life (as the sun sustains our life). She is the center of his universe now.

The line, "Parting is such sweet sorrow," makes use of an oxymoron. An oxymoron is a compact paradox, a combination of two words with incongruous or opposite meanings. The phrase, "sweet sorrow," combines two such words that have incongruous meanings.

Personification is used in "Arise fair sun and kill the envious moon" as Shakespeare was giving human actions to inanimate objects, the sun and the moon.  "Parting is such sweet sorrow" is antithesis - "sweet" and "sorrow" are antithetical, or opposite to one another, which was a common literary device used by Shakespeare to give more emphasis to the words he is contrasting.

Check the links below for more information on both personification and antithesis, as well as other literary devices.