“…make sure it’s directed at you…” is a big sticking point. I was once at The Mint, a music venue in Los Angeles, and at that time they had picnic tables for seating. The tables were oriented perpendicular to the stage, and I was on one side of a table, and a very lovely lady was seated on the other side.
She was facing away to watch the music, but she kept on turning around and looking at me. Or so I thought. It turned out that she was Sarah Michelle Geller, and when I thought she was looking at me she was actually watching the door behind me for the arrival of her date, who turned out to be Jude Law.
In another case, I was listening to music at a very small club, and on the other side of the dance floor a lovely woman was making eyes at me and even some rather suggestive gestures. It turned out that she was actually flirting with her husband who was a rather tall man standing directly behind me.
I refrained from making a fool of myself on both occasions!