First, duplicate your "top hair" layer (I'll call it "top burn") - the reason for duplicating the layer is that it will not only make the hair look thicker, but if you don't like what you're doing, you can just delete the whole layer without losing all her hair (or yours!). This is where zooming in and out comes in very handy, I usually paint with the image at least full size and then zoom out to see the whole effect.

Click on the Retouch tool, open the Tool Options window, select "burn", then open the same brush you used before (it works the same way) and adjust the settings as shown, again allowing for the size of your image. (Paint a couple of strokes on her head to see what it will look like, then undo them.)

Paint in some lowlights, again starting at the hairline and working out and down from there. These should not be as solid as the first layer, you are working more for a "streaky" effect. Duplicate your "bottom hair" layer and repeat the procedure. You can always "undo" or even go back to the paint brush and paint over some of the streaks if you think you've gone too heavy.

Now we'll make it look a little "hairier". Still using the Retouch tool, change to the "smudge" option, select the same brush, and adjust the settings as shown. Alternating between all your hair layers, "pull out" strands along the hairline, bottom and sides of the hair to get a "feathery" effect, then stroke in the body of the hair to blend and feather the lowlights into the base hair. The direction you stroke will be the direction the hair appears to be going, using different directions in the body of the hair will give it more movement and depth. (I usually use shorter strokes on top, and longer ones down the length of the hair).

Okay, it's starting to look a lot more like hair instead of a blob on her head and shoulders, but it still needs a little something - that's right, you guessed it, highlights!

This time, we're going to duplicate the "burn" layers (for the same reasons as before) and again use the Retouch tool with the same brush, but now we'll choose the "dodge" option with the following settings (again, play around with them if you need to).

Follow the same procedure as for lowlights on your top and bottom duplicated layers, keeping in mind where your eventual light source will come from in your finished image, as this will influence where the highlights are concentrated. After you've placed the highlights, switch to the smudge option and feather the highlights as you did the lowlights. This will get rid of some of the "metallic" look, if it is still too shiny for your taste, adjust the transparency of the dodge layer until it looks like you want.

Alright! You know what? If you're satisfied with how she looks, then you are done!! (With the hair, at any rate!) Add a background, do whatever else you would like, save her as a jpg and you're good to go!

Still not satisfied? On to page 3......