I have been learning this for a while. This is my most recent piece. It is a public domain image of Clara Barton. The first image is how it looked to start with.
This next image is how it looked after I fixed the image (more or less).
Following the repair job, I colorized it.
I started with this one. As you can see, the 'color' is off and there are 'issues' with the background. Changing it to Grayscale fixed the blue tint at the bottom (thanks!). Then I used mostly the patch tool and the Spot Healing Brush tool to fix any problems that I saw. Next, I separated the subject (an ancestor) from the background and slightly blurred it using Gaussian Blur.