There is no permanent solution to the question of broad shoulders due to bone structure, although a person can enhance the positive and downplay the negative aspects. Correct posture and gait, exercises to tone the upper body and dressing to draw attention from it always help, as does embracing oneself.
The quickest way to create the illusion of narrow shoulders is through clothing. Tops that are dark-colored or have vertical stripes narrow the upper body frame, while extra padding around the shoulders and square necklines worsen the situation. Similarly, stiffer fabrics increase shoulder breadth, while softer looser ones lessen the effect.