Hands are a pain.
The worst is painstakingly drawing a perfect hand.... and finding its the wrong size for the body its attached to... so which do you erase, the hand or the body?
Then again, you can just make a blob with 5 digits, and everyone will recognize it as a hand.
On the other hand, what makes a hand look real has almost nothing to do with its outline. And this is where the real problem comes in. Especially in water colors. How do you paint fine crevices? How do you paint the fine texture that is fingerprints?
I suggest, throwing down the brush and running away!
(eat some cookies in a safe corner until the panic subsides)
I measure out the head and hands before I do anything. I learned the hard way, over and over for a year! It is tough to catch the details in watercolor and gouache, but I am trying. I have a bunch of large paintings about mythological Gods and Goddesses on my to-do list. Right now, I am working on Frigg, Odin's wife. I only run away from housework! hahaha