Since I like black hair, I have it easy. One texture is all it takes.
You can use the same texture over and over. Once the texture is shrunk down to the size of a prim of hair, it is hard to notice the reuse of the texture. Plus you can rotate the texture to hide its reuse even further.
After spending two hours tweaking my head and hair settings to fit some hair last night, I am thinking of adding a "skullcap" to my hair now. This is a black colored sphere that sticks just above the surface of the head to provide a solid color base for the hair. I guess I have to see how the surface of the head interacts with it as you move. Trying to get rid of all the bald spots without ending up with this huge blob of hair can be tricky.
Highlights are going to be a little tough. You are applying them to the texture. By the time you position the prim of hair in place, it may not be in the position where it would be reflecting light. If you really wanted to make it that detailed and look good, build the prim hair and use color-coded gridded textures for the hair. The gridded textures help you plot out where the highlights will be. Then create the highlights on hair textures and apply them.
For example I would have the image black-hair-to-alpha-med.jpg as my base texture. Then depending upon my grids, I would create highlights called black-hair-to-alpha-med-h1.jpg, black-hair-to-alpha-med-h2.jpg, black-hair-to-alpha-med-h3.jpg, etc.
For brown hair I usually start out with a image 1 x 50-? pixels (depending on how fine I want to make the strands appear). Then you apply noise (to randomly get different colors) and then stretch it to 100 x 50 for example. Look it over to make sure it looks good such as not too many dark areas or light areas crowded together. This becomes your base hair image.
Now, if both ends of the hair prim tuck back into the skull, you don't have to worry about a alpha channel. You just position the cut torus hair prims into place. If you want that floating strands of hair look, then you need to use an alpha channel. The strand of hair will need to fade from a solid color to complete transparency. Otherwise you end up with the "ring" of color at the end of a hair prim. There are other tutorials the describe this effect and how to compensate for it. The easiest way is rotate the hair along the other axis until it disappears. I usually use a fade to complete transpareny at the from the 3/4 ot 7/8 to the end of the texture. I then use a tablet to draw streaks of transparency up into the rest of the hair and draw color down into the transparency. I like doing this by hand to give it a random, organic look.
As for making it shiny, have you tried making the prim shiny, reflective or whatever that property is called?
As for the lush look, I would think that would depend on the number and placement of the prims of hair. Have you tried re-arranging them to take up more volume?
