As for me, there are two aspects - construction and contour. I think that getting the construction in the first place is good way, and then you add coutours and details. But sometimes catching contour first is way to enjoy process, why not. You can read some Bammes.
For me helps to do hands more with straight lines - after all bones are straight. It makes them much more robust. And then I add fine line curves for joints, muscles, folds. Joints are important detail, even when from the first sight finger is straight.
Don't forget variation of line strength and detalisation in perspective, hands are 3d object, putting accents helps.
Btw you can draw also your own left hand, it gives you more 3d experience and detail, and it's available even somewhere in public transport )).
Practise a lot :)
Good luck! :)
edited this post on December 5, 2019 2:17pm.