Below is a old 8" x 10" photo (circa 1968) that has seen better days. it was scanned in at 600 dpi so it could be repaired in Photoshop.
Below is the repaired Photo
The images was straightened.
The white areas of the image (from where the image stuck to the glass from it's original frame) were repaired using the Spot healing Brush tool.
Adjustment layers were added to adjust the look of the image:
Brightness/ Contrast Adjustment Layer- image darkened
Hue/ Saturation Adjustment Layer
Vibrance Adjustment Layer