It's important to switch often between different subdivisions to check details and proportions. It is also important to use different sculpting methods like pinch for creating wrinkles on the chin and forehead, inflate for creating thickness of the skin between one wrinkle and another and nudge to simulate saggy looking skin. And of course, smooth, to smoothen things out. In the next image I had to use the green mask to save memory.
Now we will create pores, wrinkles and beard in the "Projection Master". In the next image I used the "simple brush" with the alpha "brush 40" and the "spray stroke" with Zsub to create pores and Zadd to create the beard.
When you leave the "Projection Master" turn on fade, deformation and normalized, and after looking at the result go back into the "PM" to create wrinkles and the eyebrow hairs and more details around the eye area.
In this image I did the wrinkles around the eye with an alpha "brush 40", and freehand stroke with 0 units in spacing.
Now leave the "PM" with the same settings as before. Check the result then start on the texture.
To do the colour map, open the texture menu and give the highest resolution. Click on the new button. Enter the "PM" again. (I did some deformations previously to make the face less symmetrical - ears, nose and eyebrows. In the next image I got a plane3D from the tool menu.