Just to resolve the thread, I though I would post the close-up again with a few notes of what I've done. Some of it is not very obvious. A higher resolution scan (800x1000) of the whole painting can be seen here:
http://www.members.shaw.ca/willenns/...ortrait800.jpg. I didn't try to fix the stitch lines this time, so the sky appears more like a sunset.
1) Straightened chin. Thanks, Steven, for this suggestion, and how to fix it. This was the most obvious problem, and I'm sure glad you caught it. I find it astonishing that I could have missed it.
2) Installed some light flares on the tiara.
3) Added more roundness to the arms, to define the light sources more.
4) Emphasized the cheekbones a little more.
5) Worked to define eyelids better.
6) Picked up some of the sunset color in the dress where such reflections could conceivably fall.
The piece is still not all it could be, but I will now be satisfied with it.
Thanks again to all who responded to my request for advice.