✔ 最佳答案
There are dozens of tutorial videos and books, they nearly all focus on breaking down the hand into geometric blocks, irregular cubes, spheres, once you have that structure you can rotate this parts into virtually any position. Then it is a process of drawing the form over the geometric structure.
It really is a question of polling various methods and finding one that makes sense to you. If I am making sketches from life I tend to draw the shadows rather than the outline – drawing from the inside out. If I make a more detailed study I will focus on the relative positions of knuckles, finger tips, wrist bones, before adding skin, flesh and sinew.