I was experimenting with some brushes in Painter, specifically some oil brushes that I could try and get looking close to the way I like to work with real oils.  It turned into a random portrait, and then I decided to save it in stages for anyone who’s curious to see how it might evolve.  In this one you can see how I’m almost drawing with my brush(my actual sketch is still somewhat visible too).  Here I’m just trying to break down the image into a light and dark pattern, and get the pattern of the shadows looking like it makes sense.  I didn’t exaggerate things as much as I usually do, but I’m still trying to give him a sense of character and push a few features beyond reality.  I had a little photo as reference, but really didn’t use it much as the sketch had everything I was looking for.  The colors are fairly muted to start, I began with a crimson palette, and just used light and darks of that color.  This is really a pretty standard way to approach painting, I’m certainly not reinventing the wheel here.  You can see near the nose where I’ve blocked in the areas that I’ll add shadow to, it might look a bit strange now, but in the next stage I’ll add the darks.  I usually save the highlights until the later stages, if I start noodling away at one area the rest of it usually falls short of what I’d like to achieve.  By slowly building up the lights I can pick one area on the image as my focal point and build the lights up to that spot.