Saw a really cute girl in bus...

So I was traveling back to my home, and I took a bus from the metro station, I saw a really really cute girl, I was trying hard not be so obvious to look at her. Coincidentally, we both got off the same stop. She was walking ahead of me, I was thinking how do i break the ice. But I didn't talk, and we went in our own ways. (Very anti-climactic ik) Tell me how do I strike a convo in these situations without looking like a creep or something? I genuinely wanted to talk to her...I may never see her again.