Working with the window.

Before adding another lamp, try moving the subject. A window changes character throughout the day: direct and crisp in the morning, broad and quiet when the sky clouds over.

Turn off the room lights and let your eyes adjust. Start with the subject beside the window, then turn a little at a time. Small changes in direction often matter more than a large change in equipment.

Leave the shadows in the picture. They give the light somewhere to go.