Like all objects, find the planes. Draw a box to find the planes as it tilts in perspective.
The fingers are cylinders that grow out the hand. Look at your own hand, draw a box that is longer than wide, then attach holes where the fingers should be.
Afterward, apply the 2D gesture that you want. Then you can combine the gesture and construction to neatly shape the hand.
Drawing hands tests your imaginative abilities as well as your eye. You want to capture the pose with your eye, and reconstruct it with your head.
