I love Blender. Therefore, a few tips:
(1) You don't have enough polygons. Your other images are for game environments, but since this is a static image you need to pump up the detail. That should be wonderfully easy using a Blender modifier called "SubSurf".
(2) Did you know that you can make a linked duplicate? You can select the upper hand then use Alt+D to create a linked duplicate, which is the lower hand. Then, any edits you make on the upper hand will also be made on the lower hand simultaneously, in realtime.
(3) Nice use of cell-shading, but it's kind of at odds with the detailed wood texture. Pick one: photo-realistic or cell-shaded. Either would look great.
(4) When I hold a pencil (Escher, too) my pinky is curled more than my ring finger, and my ring finger more than my middle finger. On the lower hand especially, that looks like an awkward pose for a hand. Also, the wrist should be narrower.
(5) If (and only if) you go for a photo-realistic approach, then bevel the edges of your pencils. Real pencils don't have hyper-sharp corners. (To bevel, go into edit mode, select all the points, then use W --> Bevel and play with the settings.)
(6) (This is not a criticism, but an FYI.) Have you tried playing with the lights? Using an area light would really affect the shadows on this one, and perhaps you would like it better.
It's a great idea, and I like your imagination. I just think there are technical weaknesses in this image. Good luck and I look forward to future art.