STEP 1:
 First, get a copy of the basemesh.pcx of the male player.  This is a blank wireframe skin of the male player model.  The Quake 2 palette should be shown on the palette toolbar.  If you don't have the pallete toolbar visible, click "View" then click "Color Palette" then click "Custom Colors".  You can then drag the color palette toolbar whereever  you like.  While  you have the Quake 2 palette loaded, now is a good time to save it.  Open the Color roll-up (Ctrl-F2) and click "Palette" from the first drop-down list.  By default, it is RGB.  Now, choose "Custom Colors" from the second drop-down list.  Click the little right-arrow at the top-right of the roll-up, and click "Save As..." and save it as quake2.cpl.  Now you can load the Quake 2 palette when ever you want by loading this .cpl file.

Now fill in the head with a light flesh color, and fill the mesh lines with a slightly darker flesh color.  Using an even darker flesh color, mark off the top of the eyebrow, the top of the nose, the bottom of the nose, the mouth, the top of the chin and the bottom of the chin.

Now it's time to start adding detail.  Click "Image" then "Convert To" then "RGB".  Now, using the paintbrush tool, start adding in some details.  Make the mouth, the cheekbones, the chin, the eyes, the eyebrows, the nose, and so on.  Use a dark skin tone for this.  Once you've made the shadows, add the highlights.  Use a light skin tone, and add highlights to the chin, the forehead, the nose, the cheekbones and anywhere else you see fit.

Blend the colors on the face, then do a little touching up with the airbrush tool.  Don't play with the darken, contrast, or hue tools.  When working in 24 bit color, you will need to use only the colors in the palette, anything else could end up with ugly results.  Once the blending is done, add the eyeballs and teeth, and any other fine details.  I reccomend using a very small brush for this.  Then start the process again for the back of the head.

The back of the head is where you draw the ears, be carefull, they're tricky.  Make the back of the head the same way you made the front; start with rough shadows and highlights, then blend and airbrush it to your liking.  A useful trick is to paint one side of the face/head, and once you like it, mirror it over to the other side.  This will help keep your skin looking consistent.

When you're finished with the head, you should load the skin into NST to do some touch up work.  NST is a very valuable skinning tool.  It lets you see how the skin wraps around the model, and  you can even paint on it in 3D.  So go get NST and tell NPherno his skin tool rocks.