Religious Imagery
Crosses permeate the film, and Romeo takes off a cross necklace to put in Juliet's hand. There is a cross in his ring, and an aerial view of the large statue of Jesus situates the movie's physical environment. The cross imagery is further presented in the stylized title of the film, Romeo + Juliet.
The first meeting
Romeo and Juliet first see each other at a costume party. She wears an angel costume with wings, and he wears chain mail. When they catch a glimpse of each other, it is through the medium of a fish tank that stands between them. This imagery—of costumes and the physical barrier of a different medium (water, which is also used throughout to represent death)—shows how they belong to different worlds that can only be traversed with great effort, and great cost.
Pool
Key scenes take place around the Capulets' pool, or other bodies of water: the beach where we first meet Romeo, the fountain where Tybalt is killed, the fishtank where the two lovers meet. In the Capulets' pool, the two lovers kiss underwater, which gives a sense of contained freedom; but water also represents an all-consuming medium, barrier, or a death-like force that "puts out the fire" and destroys passionate love.
Guns
Gun imagery is pronounced throughout the movie. The initial battle between the Capulets and Montagues occurs after close-up shots to show how the guns function like swords, and the distinction between held guns and guns that drop out of the fighters' hands reveals the power dynamic within these scenes. Guns represent the violence of the passion that is so powerful in Romeo and Juliet; they are on the one hand attractive symbols of power, and violent instruments that turn feuds into massacres.