Shakespeare engages the audience in Act I, scene 1 of Romeo and Juliet with his use of puns. A pun is a play on words. In this scene, Shakespeare uses the servents of the Capulet and Montague households to begin quarrelling. The banter back and forth exemplifies this technique of Shakespeare's. For example, in the first three lines of the play, the words coals, colliers, choler, and collar are used in the conversation between Sampson and Gregory.
Shakespeare engages the audience by bringing a lovesick Romeo onto the scene and his silliness over Rosaline makes everyone giddy with laughter.
I must say that I feel that Shakespeare's best technique for engaging his audience is the use of puns, just as kkarszes said as well. Yet, the puns that I think really grab the attention of most people are the ones used in Sampson and Gregory's conversation that relate to the sexual connotations of Sampson. He keeps discussing how he is a pretty piece of flesh and how he would push the maids of the Montagues to the wall. He and Gregory continue to play with this pun as they refer to "tool" and his naked sword. As this conversation develops we see that it begins in a sexual manner but ends in a real discussion of how Sampson needs to prove his manhood with his sword and not just empty words. As bad as this may sound, people are attracted to crude humor and that is what Shakespeare is using here in a humorous conversation between these two servants of the Capulet household.
He engages his audience with the Prologue. He tells his audience that two star-crossed lovers will take their lives. You may think he ruins the play for his audience but it has just the opposite effect. You now want to know what would cause the two individuals to take such dramatic actions.