1) If your Pen Tool painting skills are high, just draw a facial contour and hear.
In another case, find picture/photo of a woman and trace the face. Also don't forget about background layer, fill it any color.
2) In the same way draw body, dress and ears . Some parts will be under the another layers, so it does not matter if it's not nice, I recommend you to end such parts with right angles. Like this:
Remember, less amount of vertexes - less project's size.
3) Lets create face shadows. Take Pen Tool (P) draw the shadow contour fill it brown.
Shadows contours you can take from your mind or trace it from downloaded picture.
4) Then press main menu button Effect - Blur - Gaussian Blur - 16 pixels - ok.
5) In the same way draw other shadows: Armpit shadow, boobs shadow, neck shadow, and eyes shadows. But Gaussian Blur value can differ, so its your choice, try some values and tick Preview.
6) Also add shadow for lips and any other you wish.
7) Looks awfully but it's ok. After this we need to trace the nose, I draw it in three shadows, one gray and two white. And applied Gaussian Blur.
8) At last my favorite part - eyes drawing. First of all I traced the shape.
Then added green shadow inside the eyes.
Two contour shadows.
Draw two eyelashes and eyebrows without Blur.
Now create eyeballs, draw a green circle and a purple little circle inside the big.
On the tools panel press Blend Tool (W) twice - Spacing - Specified Steps - 10 - ok. Click the big circle and then small. If you want to move small circle just press menu Window - layers - Blend - open list, choose just the small one circle and move it. After achievement desired result draw a white secular.
Copy it and move to the eyes. So, last step for eyes is drawing conjunctivas. Just trace the eye and fill it white. Put this layer correctly like this:
Now she doesn't look like a beast :).
9) Hands. Draw a contour of hand, fill it red and stroke can be gray-blue. Then look up and find Variable Width Profile, choose Profile 1 (Stroke 1pt).
10) Similarly, draw fingers and second hand. But remember, invisible parts end with right angles. And put the layers correctly think what layer is bottom, what is the top.
Also add some folds and shadows.
11) Maybe we are already tired but we're not giving up. Lips......... draw any lips and fill them.
Add some white and black parts, but don't forget to Blur them. Draw shadows accessorizes and I hope you create more beautiful lady then I. :)
Some more examples: