are you using your own hand as a model?
I find it helps a lot to have a live model to draw, when I draw hands, I hold out my own hand as a refferance. I can't draw hands without a model in fact.
so Judge the difference
from a crappy hand with illproportioned fingers and odd bumps (haven't drawn a hand without a model cause I know I can't)
to this with a model:
to people: Do NOT comment on my drawing, it's just there to show how helpful using your own hand as a model can be.