"How did you make it?" is always an intriguing question to ask a photographer, because it gives permission to tell a story. When we ask "Where did you take it," that question takes us away from the photograph itself.
Asking "When did you take it" also ignores the picture subject matter, and is a prime example of a meta question. Questioning when and where puts the discussion into categories. The questioner wants to shift to their own associations and their own life experience right away.
Asking "What aperture, what shutter, what camera, how long it took" the photograph itself is again ignored. These are meta qualities. They have nothing to do with what the photograph might mean.
So, to tap into meaning, a vital interactive question we viewers can pose is: "Can you tell me the story about this photograph?" We could also just keep silent, and look, and look longer, and again, at the photograph itself.
How do gestures make a portrait more compelling? It has to do with time and motion.
Gestures are fleeting. We use them, and then move on when in conversation, unaware of our own gestures or those of others. I think many of us see a person's facial expression more than their gestures, and miss the story that the body and hands are telling.
Gestures add "moment" to a photograph. Along with voice tone, head position, and the way someone stands, they send meaningful messages of love, fear, and a range of other feelings. As photographers, we must notice what is specific about that person's gesture and how their hands can caress the unseen.
A hand gesture, for instance, increases a feeling of motion in the frame. When just a person's head is in a picture, the portrait may appear a bit stiff, but with their hands signing in the air, a sense of movement comes into their portrait. Capturing subtle gestures in the frame adds nuance and expression.
I think interesting portraits emerge when two people share a bond, and their gestures sing clearly in that moment.