cubism is all about basic abstract like representation of an image. To help you start the image i would break the image down to the basic shape....no detail...no lines just break everything down to a geometric shape. Them you can add line and shapes of shadows where needed to add interest and dimension. color is up to you....sometimes if you can pull it off black and white with like one muted color can be very impacting. As for the line work i would go with a real sketchy bold line work. You will be able to set a tone with your line work. feel free to message me or e-mail me if you have any questions about what im saying...maybe i can explain it a little better for you....let me know!