As this is an area I have been struggling with I have been having a practice at hands and feet while also looking at the work of Leonardo du Vinci.
He looked closely at the anatomy of the body to better understand it’s structure. The skin acting like a cloth over the body hiding the underlying structures of muscle and skeleton.
Here I have also tried to think about using circles and cylinders to build up my drawings but I am not sure if this helps. In the sketch of my feet in the bath I have been experimenting with the use of a coloured ground to emphasise the white highlights. I think this works well.
The pen and ink drawing , Praying Hands (1508), are beautifully drawn and show a close observation.