1- ALLUSION: The allusion is a rhetorical figure that refers or represents people, places, events, literary works, myths or artworks, but indirectly or by implication. It can also be defined as the evocation, without naming them explicitly, of people, events (historical reference), facts or supposedly known texts.
Chorus: That fair for which love groan’d for and would die, / With tender Juliet match’d, is now not fair.
Here it is an allusion, since the love that is mentioned is not explicitly said, but evokes Romeo indirectly.
2- IMAGERY: In the field of literature is called imagery to refer to the descriptive language that allows the reader to create a mental figure by using words or phrases that evoke the five senses and trigger emotional responses.
Romeo: The brightness of her cheek would shame those stars / As daylight doth a lamp.
In this sentence we can find an imagery, since there's a description that allows us to create a mental figure about the described person.
3- PERSONIFICATION: Personification is a type of metaphor that consists of attributing human properties to an animal or an object (whether concrete or abstract).
Juliet: Else would I tear the cave where Echo lies, / And make her airy tongue more hoarse than mine...
Here it is a personification, by which echo gets the human physical quality of having a tongue.
4- FORESHADOWING: Foreshadowing is a literary resource in which the author suggests certain plot developments that may come to pass later in history.It is used to excite and mentally prepare the reader to develop the narrative.
Friar Laurence: Therefore love moderately; long love doth so; / Too swift arrives as tardy as too slow.
Here we can find a foreshadow, since it talks about the fact that love can be late, anticipating the late effect of the sleeping pill that Juliet took, which caused Romeo to take his own life.
