When you visualize a scene, reveal your characters with light. Illuminating people differently will project their qualities. In particular, changing the direction from where a light originates can model a figure in a variety of ways, each creating a unique specific effect.
SIDELIGHT: Room lamps. Sunrise/Sunset. Adds dimension. Fills out the form of your character. Depth, complexity. Brings out the folds in their clothing. Used strongly in dance.
What direction of light is catching your characters? Are you playing with cast shadows or internal shadows?