Relationships are based in commonalities and ability to communicate meaningfully to the other person.
So you walk up and say "Hi I'm, _________ (and without stopping to let her respond yet) and I noticed you wore a Taylor Swift shirt the other day....It's kinda of embarrasing but I like her singing too! What other musicians do you like?"
Use the above to create your own real and honest exchange of information. When you two finally go apart from her she'll know:
-you are attracted to her/interested in what she thinks
-something about you
-that you are a quality guy/not just a immature dude wanting in her pants
-that she can be herself around you and not be embarrassed.
-that you are no wimp/confident guy.
Good luck! (even if she ends up not being interested in you....you gain experience by the confident approach you did. )