The problem is how do you engage with these other girls, other than a co-worker you've already chatted with a bit just because of work-related small talk? Do you start with, for the examples above, "so you like coffee?" or "this is a pretty great metro stop," or what?

Ah.
Good video.

I was the second guy for a long time.
I eventually decided to stop and told her how I felt, asked her out. Got rejected. Moved on.

But I haven't really pursued anyone else. I'm just kinda... working. Maybe I'll take this video to heart. Guess we'll have to see.