A couple of the best examples of Shakespeare's use of figurative language to display Romeo's love for Juliet can be found in Act 2, Scene 2. Romeo's speech at the beginning of this scene, upon seeing Juliet at her balcony, employs two metaphors to compare Juliet to celestial bodies.
The first: "It is the east, and Juliet is the sun." With this line, Romeo is comparing Juliet to the sun. Not only does this metaphor describe how brightly Juliet's beauty lights Romeo's world, but it also shows that already Romeo feels that his universe revolves around Juliet. The play was written in the 1590s, and the concept of the sun as the center of the universe was still relatively new, having been discovered by Copernicus at the beginning of the century.
The second metaphor compares Juliet's eyes to the brightest stars in the sky. He says that if her eyes were to take the place of stars in the heavens, then they would shine so brightly that the birds would be confused and believe it to be daytime.
From these strong metaphors and Romeo's passionate dialogue in this scene, it is easy to discern that he has fallen hard and fast for the fair Capulet.