What similes does Romeo use to convey Juliet's beauty?
A simile is a comparison of two unlike things using the words like or as. The comparison tends to enhance the qualities of one of those things. Immediately after seeing Juliet at Capulet's party in Act I, Scene 5, Romeo compares her beauty (it is definitely her looks he is speaking of here because he has yet to meet her) to a precious jewel:
It seems she hangs upon the cheek of night
As a rich jewel in an Ethiop’s ear
O, speak again, bright angel, for thou art
As glorious to this night, being o’er my head,
As is a wingèd messenger of heaven