It's beautiful!

Thank you Pepperwheel.

  I had a momentary urge to recolor my water into milk for fun.

The tile set is quite large and experimenting with each asset can be very time consuming.  So I haven't had time to address all of your pointers.  I did spend some time working on the background and tried a few things.


1) I tried dimming down the stones to make them seem further recessed and darker.  This attempt was more at showing only the highlights and insinuating the shape of the stones more than anything else.  I was sort of worrying that the stones were looking a bit like beans for a while but I think it improved some as I dimmed it more.

2)  This was my initial attempt at darkening the stones.  I accomplished what I was going for, but ultimately felt like it wasn't far enough perhaps.  The shadows and the highlights at this point had almost too much contrast division and it made them seem very much popping out--like bubbles.

3) I HAVE experimented with larger stones.  This version was a prior attempt that I went back and finished coloring after you mentioned larger stones.  I had basically come to the same conclusion before posting that maybe the background was too noisy and tried to blend the stones I had together.  This created, to me, a sort of jigsaw puzzle like background that was strange in the shaping enough that it distracted my eyes from the more important elements that existed on the screen.

4) After tinkering for a few minutes trying to decide how I wanted to go about experimenting with new larger stones, I simply 2x scaled my existing stone tile.  Honestly, if I were to go about redrawing new stones [larger] they would come out something very similar to this anyway, so why not?

Do any of these come closer to reaching a less noisy background that feels good?  I look for references of backgrounds of this style and many of them seem to have very evident repeating patterns.  That was a major reason I opted for smaller stones.  It felt easier to hide the grid with smaller stones that intermingled more.  The larger stones have much more recognizable shapes and patterns.

Thank you for the comment.  Just to address the other things quickly before I have an edit ready, I have been strongly considering filling in the void with more stone.  At least in a thicker pattern.  Especially after doing the drop through floor, I really felt the need to bring a more visible division between the two.  I will get on that, but it will take some time to fill all of my tile pieces in, so that might be a few days.

The surface level has been giving me trouble and I bounce between feeling like it looks good and feeling like it's too messy.  I tried a few things in an attempt to go for what you suggested, but I guess I'm not skilled enough to just draw it without some kind of idea of what to go for. Im searching for references of things done similarly, but can't find many platformers that have used a sort of floor perspective like this(as of yet).  [This is my next target area on revision though.]

Thanks again for the pointers. 

Anatomy is one of those things that really is a whole realm on its own.  The human body is so flexible that understanding it well enough to recreate it in varying poses takes a deep understanding of the skeleton and muscle underneath the skin level we portray.
I haven't spent much time on it myself at this point so I don't know that I could really be of use to you in building a better shape to your character.
However, you can equip yourself with the basic OBVIOUS tools at your disposal to save on some of the big mistakes.  Find a good reference for what you want to emulate and look at the way the light hits it.
Think about the shape of the body and look at how long arms, legs, and other parts are.  They are usually pretty similar in proportion to other body parts in MOST people.
Start small so it's easier to make large changes with less work.
Don't be afraid to save a copy or make a new layer and redraw something completely if it's screwy.
And really the biggest one of all...  You have the internet.  Most powerful tool ever invented, as far as we know.  Use it.  Research what you want to draw.  Research art.  Research drawing.  Research coloring.  Look up pictures of boobs if you can't get them shaped right.
Then practice.  Be willing to change it, even when you are frustrated with it. 
Keep at it.

Also, you really need to stop working off of a white background.  Too bright or too dark on the background will overpower your pixels and you won't be able to see what your colors are actually doing.
Find some neutral soft color to use: a soft brown, blue, or grey often works for me depending on what the base color I am using for my sprite is.

So...  Rainbow Cheetara?     http://images3.wikia.nocookie.net/__cb20111219202359/thundercats/images/8/80/Cheetara.jpg
 
Looking at your piece straight away, I can see that you are using a large amount of colors which really aren't necessary for how far along you are.
In the beginning you should perhaps start with a simple range of 3 shades for your creation.  One to set the color and a brighter version for highlight and a darker one for shading.  You can then use those to define your shape and afterwards add more colors as they are needed.

A couple more glaring oddities are the egg shape to the head.  Her chin is super pointy and crown very rounded.  Your eyes and nose are very high on the face, while your mouth is much lower.  Are your nose and mouth that separated? Her ear is on the back of her skull.  Think about these things as you look at it.  How far apart are your ears and eyes?  How high above your eyes is your hairline?

Im no expert on anatomy, but there are some simple guidelines to go by when you draw a face.  [Unless you are going for nonhuman shape, which you have established you aren't.] If you trace a finger straight down your forehead to your chin you will feel a symmetry of features, midline between the eyes, down your nose, midline lips, down your chin.  If you run a finger across from one ear to the other you will brush your finger along your eyes and clip the bridge of your nose.  Now, no two people are perfectly the same, barring twins, but these features can help you line up a face in a drawing.  You can even use lines to help you square things up and get them placed right.

There are countless untold volumes of tutorials on the web for how to draw sketches.   

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I did some work here to illustrate a few things.
1) I cropped it down to just focus on the face.
2) I tried to draw the frame box around yours, the hairline left me with a bad shape on top but this shows that your characters head either ends very quickly above the visible patch in the hair or flattens out on top.  Also of note is the way your chin curves outward from the mouth giving a sorta protruding chin or "round painted on an egg appearance" to the mouth.
3) I drew something closer to what a traditional framework for a head/face is. I tried to frame it around yours so it's a little odd in shape still.
4) I filled your primary skin palette blue to just show you the crazy number of extra colors.  I think whatever tool you are using to draw is auto anti aliasing.  The face in 1 has 90 something colors in it..
5) I cut the hair out to just show how you can isolate things in layers to work on particular portions without distraction and clashing efforts.  [Keep it as simple as you can and your work area clean.]
6) I took out the colors just to show the line-work on the face and how oddly shaped and jaggy it is on the one side.
7) I added a color to your palette and cleaned it up some.  Tried giving it a more humanoid shape, though I clearly kept to your original shape and allowed it to have a sort of pointy chin, shortened/rounded crown, and little to no pronunciation at the nape conjunction to the skull.  This kept to your initial portrayal, but left it with more shape. It feels like a toy doll now to me and I would definitely try to correct more of the anatomy, unless you want it to look sorta unusual.
8 ) I stuck your hair back on it to show how much the shape changed.

Now you can take these edits with a grain of salt.  I am no master of anatomy or even faces.  It IS your piece, so my idea may be way off from what you want.  Mine looks differently colored but that is only because I haven't shaded, or highlighted anything.   That comes next.  I didn't deal with the neck aside from cleaning up the mess of extra colors there.
Definitely check into the auto AA though.  It will make pixeling nearly impossible.