definitely draw realistic hands. If you are truly serious about your artistic improvement, you need to stop drawing anime. You can go back to it later once you've learned the basics, but until you have a firm grasp of anatomy (not to mention value/light, perspective, color theory, composition, etc.) you are not ready to stylize in any capacity.
here's a simple tutorial on drawing hands:
here
That's just the basics but really that's better than being coached along each line because that way you don't learn as much (in my opinion).
Look at the bones in the hand.
clicky. The position of the bones is very helpful in anatomy.
Good luck.