The exercise of producing the drawing was made easier by conceptualising and naming the different abstract shapes that make the the overall impression (I managed to find a cat, a swan, a scimitar, a fish and a kiwi). This really helped in understanding the gesture of the individual folds of the ear, enabling me to arrange the various masses accurately.
Getting the correct values was the second big challenge. It is relatively easy to get two adjacent values in the correct relationship, but much more difficult to juggle the whole light impression so that the drawing accurately matches nature. In this instance, along with the smaller planes there were two distinct larger planes of the ear (the upper part tipping towards the viewer from the top to the middle, the lower part tipping away from the middle to the bottom). This took quite a while to get right.
Overall I'm really pleased with the drawing - particularly the handling of the shapes. The finish is not quite as refined as I'd like, though - and the drawing doesn't seem to 'pop' out of the page to the extent I was hoping for. Something to aim for in my next one, which I kicked off a couple of days ago.