These are some Kawasaki's works. They're very particular, a sort of balanced combination between mangas and Art Nouveau. The most important features I'll try to copy are:
1. the wood background
2. a large head
3. thin long eyes and little nose and mouth
4. the particular coloration of the skin
5. defined edges
6. a weird shape of the hair
7. the fluctuating arms

I'm sorry: it will be a veeery long tutorial with a lot of images and steps. I want to be detailed as more as possible.

I use Photoshop 7.0

Take your photo. A good photo is frontal, represents a girl and possibly her arms, in some nice pose.

Mine is this:
http://www.flickr.com/photos/aehohikaruki/422890144/sizes/o/

Your actual layers are:
1. a white background (Background)
2. your picture (Original)
So, select with the Marquee tool the head of the girl, click the right button of the mouse and create a Layer via Copy. Call it Head.

To create a Kawasaki head distort the Head layer (edit > transform > distort). Follow the arrows of the example to enlarge the head and make more thin the chin.
Then, change the head layer opacity to 50% to superimpose the new head to the original one. When it's in the right place (the necks coincide) return the opacity to 100%.

Return to the Original layer and select with the Marquee tool (or Lazo tool if you prefer, it's the same) just the eyes. Click with the right button and create a Layer via Copy; call it Eyes.

Make the eyes thinner reducing the height of the layer (edit > transform > scale) like in the image. Then move the eyes down, a little bit under the real eyes.

Return to Original layer and select with the rectangular Marquee tool the eyelids zone. Create a new Layer via Copy in the usual way and call the new layer Eyelids.

Make the eyelids higher dragging the bottom part of the selection (edit > transform > scale).

Make visible both the Eyes and the Eyelids layers. Work on them with the Eraser tool with a little size, and faded edges, to delete around the eyes (in the Eyes layer) and under them (in the Eyelids layer).

Melt the Eyes layer with Eyelids layer (click on the higher layer, probably it's the last one you've created, and press Ctrl+E; call the melted layer simply Eyes).

Return to Original layer and select with the rectangular Marquee tool the nose. Create a new Layer via Copy and call it Nose.

Modify it reducing the lenght of the bottom part (edit > transform > distort).

Probably you'll see a straight line between the new nose and the original face. Fix the zone deleting with a shaded Eraser tool the edges of the Nose layer and deleting the old nose in the Original layer with the Clone stamp tool or the healing Brush tool until the skin is perfect.

Return to Head layer.
To make the mouth thinner and more little go to filter > liquify.
To be sure you won't modify other parts of the face (for example the nose) use the Freeze tool to draw the edges of the mouth.
Then work with the Pucker tool to make it more short and the Bloat tool to make the bottom lip bigger.

In my photo it's difficult seeing the difference because "my" girl already had a beautiful mouth, just a bit too large (to be a Kawasaki girl).

Now you can merge the Eyes - Nose layers with the Head layer (Ctrl+E).

Return to Original layer and make it more little (more "young"). Use edit > transform > scale and make the layer to the 90% of the initial dimention.

Create a New layer (layer > new > layer) and call it Edges.

With the Pen tool follow the head edges (make curves not a simple broken line), then the neck, the shoulders and the arms. It depends on your source, but if possible try to draw at least a fluctuating arm.
The neck have to be drawn more thin and the shoulders a little bit squared off.

When you finish to draw th path click with the right button of the mouse on your image and select Stroke path.
Select as tool the Brush, and remember to have the Brush tool setted on a little size (2-4 pixels, but it depends on your image dimension), definite edges and black color.
Don't simulate pressure.

Keep always the Edges layer as the most high in the Layers panel.

In the Edges layer use the Magic Wand tool to select the background part. To make the selection more precise go to select > modify > expand and expand the selection by 2 pixels.
Now return to Head layers and delete the selection.

Reselect the background part in the same way (Magic Wand tool in the Edges layer plus expansion), and in the Head layer delete the selection.

Melt the Head layer and the Original layer (Ctrl+E) in a layer that we'll call Girl and duplicate it (layer > duplicate layer); call it Girl2.

Turn Girl2 layer invisible and work on Girl layer with the Eraser tool (medium size, round shape, shaded edges and better a 30% opacity). Delete all the trunk and the neck, and the higher part of the arms shading (and all the clothes if your girl wears long sleeves).

Go to Edges layer and select the background (expand by 2 pixels) and invert the selection (select > invert).

Create a New layer calling it Color. With the Eyedropper tool chose a pink color taking it from the girl skin.
In the Color layer fill the selection with the Pain Bucket tool (pink color obviously).

The Color layer must stay under the Girl layer.

Now work on Color layer with the Brush tool (medium size, 25% opacity, dry brush similar to the one of the example): picking brown and dark colors from the girl image create the neck shadow, and picking pink and red, for example from cheeks and lips, paint the shoulders.

Go to Girl layer and make the contrast higher (image > adjustments > curves) and copy the example curve. Then set the layer style on Darken.

Melt Girl layer and Color layer (Ctrl+E) and call it Girl.

Go to filter > noise > dust and scratches and set it on 2-3 pixels radius.

Duplicate Girl2 layer, keep it invisible and work on the new layer (Girl3).
With a round shaded medium Eraser tool delete all, except eyes, nose and mouth. Then set the Eraser tool opacity to 10%-20% and make eyes, nose and mouth a little bit transparent.

Girl3 layer must be higher than Girl layer.

Work on a New layer (call it White) with a little shaded white Brush tool setted on a low opacity (for example 25%). Put color in the internal part of the eyes, on the nose, on the lower lip and in the superior edge of the higher lip.

Blur the color using filter > blur > gaussian blur setted on 1-2 pixels radius.

Melt White layer with Girl3 layer.

Go to Edges layer and select the neck-shoulder part (expand by 2).
Go to Girl layer and select the Quick Mask mode.
Use the Gradient tool to create a shade.
Return in Standard mode and you'll see that the lower part of the trunk is selected. Delete the selection (Ctrl+X).

Create a New layer (call it Red).
In this new layer color, with a medium size-dry kind-red Brush tool (with low opacity, for example 25%) the elbows and the hands, expecially the fingers.
Then delete all it's out from the edges (of the Edges layer).

Go to filters > noise > dust and scratches and set a 2-3 pixels radius.

Melt Red layer with Girl layer.

Create New layer and put there a wood texture image. Call it Wood.

Mine is:
http://www.flickr.com/photos/jaredkc/321099676/sizes/l/

Melt Girl3 layer with Girl layer (Ctrl+E). Call it Girl and duplicate it (layer > duplicate layer) in Girl3.

Probably you won't need the old Girl2 layer, but I usually duplicate often my layers, so in case I wrong something I have my old steps still perfect.

Now use on Girl layer the Dry brush effect (filter > artistic > dry brush) with a little size (2) and and high brush detail (8).
Turn the layer opacity to 50%.

Now set the Girl3 layer to 60% opacity.

The right order of your layers is the one shown in the example.

Create a New layer (call it Edges2).

Go to Edges layer: with the Magic Wand tool select the background; then invert the selection (select > inverse).
Return to Edges2 layer and fill the selection of white with the Paint Bucket tool. Deselect.

Blur the layer (filter > blur > gaussian blur) with a 1-2 pixels radius Gaussian blur.

Go to Edges layer; select the background (Magic Wand tool, expand by 2) and invert.
Return to Edges2 layer and delete the selection. It will remain a white shaded border.

Probably the continuous "go to Edges layer and select the background" could be spared if you'd save the selection. But I've never done it so.. I can't teach something I don't know and anyway I don't want to use.

If like in my example your wood is too bright you can go to Wood layer and make it darker with a curve like mine (image > adjustments > curves).

Create a New layer (call it Shade).
With your favourite Brush tool shape add the color you prefer (I used blue but it's just an example).
Then blur it (filter > blur > gaussian blur) with a little radius, for example 3 pixels.

Set the layer style to Color.

You can change the color of the wood, of the colored part and of the girl going on the right layer and mix hue, saturation and lightness (image > adjustments > hue/saturation).

I decided to make all more desaturated to make the work more similar to Audrey Kawasaki style, and I changed the blue in pink because I've thought it was a better color for my girl.

The work could be considered complete.

I personally decided to add even the hair, and if you want you can add it too.
Create a New layer (call it Hair). With the Pen tool draw the hair shape. Use a lot of soft curves. Isn't necessary to draw well even the lower part of the hair, because we'll shade it.

Transform the path in a selection clicking with the right button of the mouse on your image (make selection > new; 0 feather radius and tick the anti-aliased).
Now take the Gradient tool with the color you want to use for the hair and make it more dense in the higher part (use the preset Foreground to Transparent).

With the Eraser tool (choose you the size, ect) delete the color where it appears under the girl, even under the face because the 2 Girl layers are setted on 60% and 50% of opacity.

Hint: in next step you'll need again the path you've drawn for the hair, so better if you copy it and select just one of them to make the selection, saving the second one for next step!

In a New layer (Edges3) re-draw the path with the Pen tool (or you use the second path if you duplicated it before) and stroke it with the same brush size you used for the black edges (in Edges layer).

Then go in Hair layer and delete with a little Eraser tool all is out from the black edge. In the Edges2 layer instead, delete the white border in the part where the head touches the hair, and close to the shoulder use an Eraser tool with a low opacity to shade the white border.

Go to Edges3 layer and select the black line with the Magic Wand tool.
Create a New layer (call it Edges4) and fill the selection with the Paint Bucket tool with white.
Deselect and blur the layer (filter > blur > gaussian blur) setted on 3 pixels radius.
Then delete with a little Eraser tool the internal part of white.

Now you can melt (Ctrl+E) all the Edges layers (the first one with 2, 3 and 4), just remember to keep Edges and Edges3 higher than the other 2 (the white ones).

Now you should have the layers in this order:
1. Edges
2. Girl3
3. Girl
4. Shade
5. Wood

I consider the tutorial finished, but obvioulsy you can continue changing colors, hue and saturation, contrast, and so on, or add some flowers or animals using the same technique (black edge, white edge, dry brush, ect.)

*
I hope you like the tutorial (and the result) and that I didn't write any error (too many layers, I could had confuse something). For any doubt you can write me.

Thank you.