I have finally been able to join a life drawing group. Once a week I get to join others at the local university for a life drawing course. The instructors are two senior art majors and they do not seem the least intimidated by correcting and instructing a group of their parents' age.
We have been working in charcoal. The last couple of sessions have been working o toned paper, lifting out highlights and drawing in darks. This is a new method of drawing for me, and I find it a great aid to start with the middle value and then work by subtraction back to the lights.
Usually in both ink and watercolour I start from the lightest values and gradually build up the darks, always taking care to preserve the lights. Charcoal is turning that on its head.
I will note that figure drawing has me working considerably larger (18x24 inches) than I am used to. It is also considerably easier for me to draw the figure from photographs than from life.