When I used to sketch, I always found hands difficult to portray correctly. I found faces easier.
I'm glad to see you say you will continue to practice. From the few artists I have known, I would say that they day you stop practising, because you now know enough to just concentrate on drawing the picture, is the day you stop being an artist and revert to being just an illustrator.
I think you can never stop from practicing if you want to constantly improve what you are doing, no matter what that is. In this case I am willing to spend the time on drawing because I just enjoy it so much :)