How does Shakespeare engage the interest of the audience in the ballroom scene?

The two references that Capulet makes to age develop the major theme to the play because the two main characters, Romeo and Juliet are also very young and wish to get married at a young age to prove their love to each other.

The two lines "Come, musicians play" and "A hall, a hall, give room! and foot it, girls." Show that Capulet is very keen for the ball to begin. These are lines 24 and 25.

Shakespeare makes this scene particularly engaging for the audience at this point by having music playing and girls dancing around to the music. Also, there are lots of guests crowded around in a circle to watch the girls dancing in the middle.

Lines 35 - 38 comment on Capulets further reference to age. This gives us the impression of the speediness of time by saying how old his son is (30 years old) and how he is getting on and that he is too old to dance "For you and I are past our dancing days."

Romeo has just entered the stage, so I would direct the actors to move away from him, but to be normal to him as he is wearing a mask and people cannot recognise him. The dancers would continue to dance, as he is just another guest to them, but they would move away from the door, as otherwise Romeo wouldn't be the center of attention. Capulet would be very near to him as he greets him like another guest.

From Romeos first speech, you can tell that he has spotted Juliet from the entrance hall. The way in which the actor should deliver the line is whispering in the serving mans ear, gently leaning over to him but still looking at Juliet.

Romeos speech in praise of Juliet's beauty speech is very imaginative. He compares her to someone who teaches torches to burn bright and that she has beauty that is too rich for use, for earth too dear. He also compares her to a rich jewel in an Ethiop's ear. He loves her at his first sight "Did my heart love till now?" this is a rhetorical question asked by Romeo to the audience. His speech is written in rhyming couplets with a regular rhythm, occasionally broken by an irregularity in the rhythm - this is so it sounds like a real speech. Shakespeare gives such formal verse to characters sometimes because he doesn't want the audience to forget that the play is supposed to be serious, not just a comedy but also a tragic romance.

Shakespeare introduces a note of tension after Romeos speech by letting the audience know that Tybalt heard Romeos speech. Tybalt is also a family member of Juliet and Romeo does not know that he is talking loud enough to let Tybalt hear. Tybalt then swears to kill Romeo, but does not tell him to his face, but tells the Capulet, his uncle. Capulet reprimands him and tells him that there will be no duelling at his party, and tells Tybalt to let Romeo get on with what he is doing, as he wants no trouble. This heightens the dramatic tension at this point in the play as the audience thinks that there will shortly be a big fight in which Romeo will be mutually wounded and will die.

Capulets speech, lines 82 - 87 is dramatically engaging as he is being happy and saying mad things, like "You are a princox". I would advise the actor to play this part with a very happy mood, and tell him to bounce and prance around the stage, rather loud but not loud enough to cause a scene. The actor must be happy when performing the part otherwise the effect will not be as great as it should be.