Gesture is trying to capture the main action of a character with as few lines as possible. It helps to align the construction of a character to a base so it has rhythm and energy.
Just as you might know, I almost always start my drawings with a gestural idea/sketch. Later it can change in some parts like limbs, head, etc. but the main action remains.
Main gesture here is just 4 lines or 5 lines. Even if the gesture is not shown in the later stages of the drawing, the final drawing should be able to convey the initial feeling/energy of the gesture.
The notes here are some aesthetically pleasing concepts I search while doing gestures that I later try to translate to final shapes.