How does Shakespeare use dramatic irony and juxtaposition to strengthen Romeo and Juliet?

Romeo and Juliet begins with a prologue that creates dramatic irony by telling the audience what will happen. We know that “A pair of star-cross'd lovers take their life,” thus ending “their parents' strife.” The characters have the occasional sense of foreboding, but they are largely ignorant of their fate.

One moment that demonstrates a character’s innocence in contrast to the audience’s knowledge is Juliet’s speech as she eagerly awaits Romeo’s return. She wishes for...

Romeo and Juliet begins with a prologue that creates dramatic irony by telling the audience what will happen. We know that “A pair of star-cross'd lovers take their life,” thus ending “their parents' strife.” The characters have the occasional sense of foreboding, but they are largely ignorant of their fate.

One moment that demonstrates a character’s innocence in contrast to the audience’s knowledge is Juliet’s speech as she eagerly awaits Romeo’s return. She wishes for the sun to set so she can be with him:

Spread thy close curtain, love-performing night,
That runaway's eyes may wink and Romeo
Leap to these arms, untalk'd of and unseen.

This soliloquy is juxtaposed to contrast with the previous scene in which Tybalt killed Mercutio, Romeo killed Tybalt, and the prince banished Romeo. Completely unaware of these tragedies, Juliet’s yearning for Romeo is made all the more poignant.

The play’s conclusion is rife with dramatic irony. The audience knows Juliet faked her death, but the only character who knows this is Friar Lawrence. As a result, Romeo’s ignorance about the matter is a major source of suspense until the end. He also has a deeply ironic dream the night before his death: “My dreams presage some joyful news at hand.” Romeo dreamt that Juliet revived him from death with a kiss. Instead, Romeo poisons himself and dies upon kissing Juliet, who then awakens and kisses Romeo before stabbing herself. The fact that Romeo died moments before Juliet woke up is another great irony.

By juxtaposing contradictory scenes and utilizing dramatic irony, Shakespeare plays with the audience’s emotions and creates an engrossing sense of tension.