Today, I took a three and a half hour class in drawing hands at Hipbone Studio. It was a very useful class with good examples, handouts, and instruction. The instructor, Jeff Burke, pointed out landmarks on hands, even marking his own so that we could see the lines of knuckles and other bones. So much of drawing is observing and he pointed out many things to observe.
I hadn't realized how difficult it is for a model to hold a hand pose for 30 minutes at a time, but we had an excellent model.
I won't show my first attempts because they have a noodle-finger look to them. You'll just have to take my word that I improved.