A list is fine, but you can keep it brief.  A job for 5 sprites is much different in scope from a job for 30, or 100.  Knowing roughly how many animations per character is good as well. 

It would be useful to know if you have any schedule requirements or payment method restrictions (such a only paying by Paypal, or only wire transfer, or whatnot).  When it comes to amount, hmm. 

Assuming you can pay industry rates, say you've got planned art budget of about X, while keeping a little held back to negotiate for better quality, or pay for extra rework, or even an unexpected completion bonus.  Potential artists will take a look at the scope of work, the budget and schedule requirements, and be able to assess if they want to apply.  Wage per hour doesn't really enter into it on your end because you have a fixed scope of work. 

My two cents,
Tourist

Did a partial edit.  Man, I am out of practice.  Head, neck (too much neck maybe), one shoulder, upper torso.  Gave her some pants, I mean come on.  Cheesecake or not, that's just an awful costume.  I included some intermediate copies of the face.  Helm's edit did a better job on the arms and legs than I would have anyway.



I think you need to work on anatomy study and expressing form (3d-ness).   Also, too many colors in the original, I think.  You could get away with (skin, blue, extra saturated stuff like lips, extra desaturated stuff for silver and background), 5 colors each for about 20 colors total.  But other people here are better at colors than I am.

Steps on the face I used:

• Given the size of the head, determine the size of the eye (eye width is approximately head height divided by 6 or 7). 
• Sketch out a couple of eye shapes, and pick one.
• Put the eyes in the head.
• Sketch the other reference points: base of the nose, mouth, chin, hairline.  Add a preliminary cheek and jaw line.  Move the eyebrows around as needed.
• Fill in lights and shadows.  This is to add in the shape of the underlying skull.  So the eyes get sockets, the nose gets lighter, as do the cheeks, chin and forehead.  I didn't shade in the eyeballs or lips yet, just the shapes of the head.  I think I added a bit of AA to the jawline.  Oh, I added a lot to the top of the skull too - she had a very flat head. No reference used.
• Then go back and color in the actual eyeball, and lips.  This got me to the third face on the right.  I confess I think I like this one the best, but at the time I wanted to tweak it some.
• The last head on the right is the same face but made thinner by one pixel.  Then I tried a rounder jaw, which is what is in the full sized version.

Clarity is very important.  The eye shapes I used are not much different from the eye shapes you used, but I kept the shading simple.   But mostly it is the lack of form, and wonky anatomy that is hindering you. 

Hope this helps,
Tourist

It looks like you're reinventing Zbrush.  Zbrush is mostly 3d and surface modeling these days, but it started with 2d brushes that painted pixels with surface normals.  Or maybe just a z-buffer that was used for real-time lighting, the effect is the same. 

The user could choose from several brushes, some that would paint flat, some that would build up the image, others that would flatten it down.  These could be combined with various colors or textures so that you could paint a color and height at the same time.  Lighting was separate, and a user could alter the lighting direction at any time.

Here is a link that sort of covers this feature: http://www.pixologic.com/zbrush/features/2_5D/. 


If you're using software for processing the normals, maybe take a look at these articles.  They were written before pixel shaders were around, so the code might not be useful, but the math and logic are still good. 

http://www.gamedev.net/reference/articles/article1191.asp
http://www.gamedev.net/page/resources/_/technical/math-and-physics/higher-accuracy-quantized-normals-r1252

Representing the data as unit normals (where x^2 + y^2 = z^2) might be better than using independent variables.  With independent variables,  x = y = z = 64 has the same normal as x = y = z = 128.  Or just store it as theta and rho (or even cos(theta) and rho), which would front load the calculations but be faster if you were planning to do this real time in a game engine.

Hope this helps,
Tourist

Here is a tutorial for drawing drapery and draped cloth from ConceptArt.org.  It is not specific to pixel art.  Also, large images.

http://conceptart.org/forums/showthread.php?t=14739

In general, you can also look at real world examples.  Get a sheet or a blanket and drape it over your shoulders, or even a piece of furniture in order to study.

Hope this helps,
Tourist