I am in the same situation, my students have poor hand
skills - many of them can not draw neatly because no
one has taught them to hold a pencil in any way but
basically a fist. Apparently that is no longer taught
in elementary school.
I watched a boy draw today, to see if there was any
way I could help him improve having ANY control over
the line, and I truly think I can't.
However, I am not stressing neat drawing, I stress
un-neat drawing. I am really concentrating on getting
them to sketch, make preliminary marks, etc., they all
try to draw like a coloring book.