Practice from reference, folks!
From various places, mostly from these 3 lovely stock deviants.
Also several of my own hands and feet in there. How nice of them to volunteer! Although my sticky-out radius bone occasionally does freak people out. They say, "Ginger what is that THING on your wrist augh
you need to get that removed!" to which I respond "...That's supposed to be there. Really it is. Drawing would be pretty hard without it..."