Insert the image.
Duplicate the image layer.
Adjust top image layer, using appropriate tools.
Curves have been applied.
The result.
Add another layer to start making some local adjustments.
Start tweaking numbers
In this instance I've increased the value by about 10 units, almost a zone.
Brush all layers in and out in varying opacities as needed, be careful about when to stop. The conversion to jpeg seems to have buggered up the subtlety of the brushing in, trust it is smooth and subtle.
The power of this Application is that you are concentrating on the image, surrounded by minimal palettes, no other clutter on the desktop, and the application is only working and using the pixels you need to see and work on.
*or, how to procrastinate more than needed!