What are 2 or 3 examples of Romeo being a superficial character and only caring about outward appearance.
1. He fell in love with Juliet at first sight.
Romeo is mercurial and definitely prefers outward beauty. In the beginning he even makes a comment about how it is a waste that Rosaline swore off men because her beauty will go to waste. Romeo also falls in love almost instantly, because Juliet is pretty, and he focuses on her being beautiful.
Friar Lawrence also says "young men's love then lies not truly in their hearts but in their eyes." Romeo says over and over again that he loves Rosaline, but she will not have him. There is also some discussion about Rosaline declaring she will remain a virgin forever. This could be a reference to a refusal of marriage but it could also simply be a refusal of Romeo's romantic advances. Romeo quickly forgets his feelings for Rosaline ("he jests at scars that never felt the wound") and rushes into a relationship with Juliet. We do not see a deep connection to her but simply a superficial attraction.
The fact that he falls totally in love with Juliet so quickly after being totally in love with Rosaline suggests that he is superficial as well. Friar Laurence chides him about this, and even says that reason Rosaline didn't love him was because she knew he was so superficial:
O, she knew well
Thy love did read by rote, and could not spell.
As far as I can recalll, most of his words regarding Juliet are about her appearance rather than her personality. Such as:
She doth teach the torches to burn bright.
This is probably a result of your #1, "He fell in love at first sight." It's probably not possible to fall in love at first sight without being primarily moved by appearance.