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.
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.