"See how she leans her cheek upon her hand!
This is a quotation by Romeo in Act II Scene II. Romeo is delivering a soliloquy as he stands in the Capulet's fruit garden and is viewing Juliet as she stands on her balcony. This quote means that he wished he was a glove on her hand. Juliet placed her hand on her cheek. Romeo is thinking that if he were a glove on Juliet's hand then he would be able to touch her skin. He is very much in love with Juliet and the only way he can get close to her is to watch her from below her balcony.
This line is from the balcony scene in Romeo and Juliet. Romeo is the speaker. Juliet appears at the window and is looking out into the night. Romeo stands outside Juliet's window and professes his love for the young Juliet.
"See how she leans her cheek upon her hand!" implies a stage direction. Shakespeare didn't write directions like 'Juliet sits on the bed' however he gives clues to the actor within the text. Juliet has propped her head up on her hand as she gazes out at the stars. Romeo would like to be near enough to touch the lovely Juliet in much the same way that a glove on her hand would touch her cheek. He wishes he could touch her face.
Romeo spoke these lines. He was secretly gazing at Juliet from her parent's orchard as she stood in her bedroom window. Romeo and Juliet had just met and fallen in love earlier in the evening. Romeo is wishing that he was physically closer to Juliet (the glove upon [her] hand).