First, what do the the bands around the sketched arm do? Just there to get the shape of the arm down?
Exactly. Just a visual guide to think about foreshortening and shape. I usually do this for more surface, but there's not a lot of difficulty in this sketch as far as shapes go, pretty straightforward.
And, more personally, why did you choose to draw such a uh, generic high fantasy scene with Conanesque barbarian and everything, anyway? 
This isn't art for me, it's just practise. Most people revert to their basic themes when they're not exploring new ground, so yeah, I used to draw a lot of barbarians as a child and I often still do when I get the urge to draw MUSCLE I WANT MUSCLE I WILL SHOW YOU MUSCLE, you know. Besides, I urge you to consider the cliche for what it is: pulp fantasy. Quite different from high fantasy 'elves and wizards'. I enjoy Conan or Fahfr and the Grey Mouser much more than Lord of the Rings and that type of fantasy. Cruel steel to end your foul sorcery, wizard! I still find that sort of thing much more appealing than dwarves and elves, although not as appealing as robots. Robots win.
If that was directed to me, then i want to say that i actually intended to emulate what Yoji Shinkawa does best with his insane ink brushing skills. Unfortunately his technique is just so advanced, i was only able to emulate the shading.
You know it's actually hard to tell what your skill level is from these? Why don't you try some simple pencil drawings of humans and telephones and show us. If you want critique, that is.
One thing that i noticed immediately was his eyes. They sort of look like tired eyes? As if he doesn't care incredibly about where he's swinging his sword. Perhaps it's not just his eyes that're showing this, could be his whole face. It's really generic but i get the feeling a more angry, intense expression would work better. In fact, like your original sketch perhaps?
I actually toned down the anger in the original expression lots purposefully because if you're familiar with Conan lore, he's killed a lot of people, been to a lot of battlefields, it's a dayjob so to speak. What I
did add instead to the face is a bit of sadistic glee, like 'oh you're going to get the sword in the head soon!' to go along with that he's going to strike a distracted enemy and whatnot. He's not very nice! Most barbarians aren't! So yeah, the expression with the tired eyes is deliberate. When I render more I might change the face a bit to half-close one of the two eyes because there'll be a jet of blood trailing the upstroke of the sword. Perhaps. Perhaps it'll be too flashy and I won't do it. I might work on this more soon, actually! Thanks for the interest and comments.
edit: carrying on
