Juliet to her mother (verbal irony)
Juliet uses words when interacting with her mother after meeting Romeo that do not mean what they ordinarily would. She signifies—to herself, and to the astute reader—concepts that would never be picked up by someone basing an interpretation only on the words' denotative meaning. She intends to communicate with her mother at another level; for example, the night before she "dies," she tells her mother she does not know the next time they will be together.
Introductory montage (dramatic irony)
The film begins with an invocation to the entire story. From the beginning, the viewer understands that the love between Romeo and Juliet will not survive, so we witness the development of their relationship with the knowledge that the film ends tragically. Their choices appear poorly-thought-out to the audience who knows how these choices will ruin the pair's chances at a happy and long life together, but Romeo and Juliet believe they are acting in their best interest.
Poison (dramatic and situational irony)
When Romeo chooses to drink the poison he brought with him to see Juliet, the viewer has been shown Juliet to be stirring. Her hand moves and her eyes begin to open, so we can tell—using the previous information—that she will wake up just after he finishes the vial. Then, it will be too late for him to revoke the action of suicide.
Party (situational irony)
Romeo attends a party at his rivals' home and meets a beautiful young woman. He does not expect the woman to be a hostess of the party, so he expects their first moments together to take place in an environment as unknown to her as to him. However, she knows the house as her own, so she gets to know him first in the location she has been exposed to since birth.
