Answer: "By giving liberty unto thine eyes. Examine other beauties" (Shakespeare, 1.1. 217-218). Essentially, Benvolio advises Romeo to forget about the woman who is not in love with him and to look upon other beautiful women.
Benvolio then suggests that Romeo should try to get over Rosaline by going to the ball and looking upon “all the admired beauties of Verona” (I. ii. 85). Benvolio insists: “Compare her face with some that I shall show, / And I will make thee think thy swan a crow”