Over the past couple of weeks, there's been this really cute girl who sits near me inside a coffee shop, which has a cozy, "productive" vibe to it -- everyone's doing work on their laptops. I want to start a conversation with this girl, but there's one significant obstacle: she's always wearing her headphones.

So, my question is:

How can I effectively and politely start a conversation with this girl who's sitting next to me and wearing headphones?