Yes a part of it is having your eyes open to looking for those incoming flirts too. Don’t worry, like any other muscle, it grows with use.
It started when I noticed these & acted upon them in my own life, but yet again I see these things happen with guys I coach all the time and I see how they don’t notice them coming at them.
With my pointing them out and their remembering the move they saw, but not understanding the signal, they identify them more as time goes on.
The second half of all of that is the clear recognition and the action upon it. It doesn’t even have to be witty or clever or anything, just responded to.
It doesn’t matter if you joking is really silly or you stutter a reply or the content of what you say to her at all. It is just responding in any way, that is all.
Then she knows you detected her flirt, and she was successful in her small coy move to get your attention. This is a time to let her have her winning glory. To reward her small moves will encourage more of them and give her those good feelings you have for then coming at you.