Go over the main themes of the play before you begin reading the play. Many students will make a connection with the idea of controlling parents, feuding families, extreme loyalty to friends and family, and, of course, love at first sight. These are things that most typical teenagers are dealing with on a first hand basis as they go about their everyday lives. Many girls will identify with the frustration of parents wanting them to be with someone other than the boy the girl loves and boys will identify with the concept of sticking up for your friends no matter what the cost.
Translate Shakespeare's English into modern English. Students tend to get bogged down in the "the's" and "thou's" and give up very easily when reading. Create a conversion chart and have the students copy it in their notes so they can refer to it frequently as they read the text. It is also helpful to discuss how many of the words we use today were actually created by William Shakespeare. They often gain respect for the Bard as they realize how much he has influenced our modern language.
Allow the students an opportunity to rework a scene from Romeo and Juliet from a modern perspective. Students may choose to rewrite the meeting/party scene to be set at a typical high school party at someone's house, or at a school dance. The balcony scene could be rewritten as a texting conversation or have Romeo and Juliet write on each other's Facebook wall.
Show movies and video clips that are inspired by or related to Romeo and Juliet. Students make the connections and begin to understand how influential the famous play has been on our society. West Side Story is always a great option.