but as others above have said, its also difficult. It has visual properties that nothing else does so its something that has to be mastered to a certain extent separately than the usual ways of painting or drawing. You have to see it in a different way than you see landscapes or Still lives. Just like painting flowers is very different from painting the vase theyre in or the clouds in the sky. Each element must be looked at in its own way.
My suggestion is that you train your eye to see the uniqueness in drapery. If I were your teacher I would ask you to take any part of the scarf and work on that. First I would want you to draw it. You can use graphite pencil which will make you to really look at each Highlight and shadow. Or you can use color pencils, which will help you discern the subtle hues of each color.
I particularly like the lower left and bottom of the scarf. Draw that all by itself. By doing this the concentration involved will put you into your right brain very quickly. You will be in the zone so to speak. You will marvel at what comes out.