Define the action precisely
Choose an action with an obvious starting point: a step, a turn, a reach or a shift of weight. Explain where it begins and where it should finish. A repeatable action lets the person concentrate on the feeling of the movement rather than guessing what the camera needs.
Leave room around the gesture
Check where hands, clothing and the direction of the gaze travel during the action. A frame that feels generous in a still pose can become cramped as soon as the movement begins. Widen the composition until the gesture has enough space to be understood.
Change one variable
When reviewing a sequence, separate timing from lighting and camera position. Repeat a promising movement while adjusting only one of those variables. This makes it easier to learn why a frame works and avoids losing a useful gesture in a succession of unrelated experiments.