The good technique is to use a "luminosity mask". This makes for very progressive touch up. There is the canonical tutorial by PatDavid that explains the principle very well.
In action it looks like this:
Starting with this image where the shadows along the quay are a bit too dark:
You create a luminosity mask that extracts the very dark pixels (DDD using PatDavid's conventions)
and apply Curves (Brightness-Contrast isn't very good at the ends of the histogram).
You can use the method expounded in the tutorial to create the masks, but I also have a script with some pre-cooked ones and you can create your own (or use part of the script just to extract a luminosity channel).
In action it looks like this:
Starting with this image where the shadows along the quay are a bit too dark:
You create a luminosity mask that extracts the very dark pixels (DDD using PatDavid's conventions)
and apply Curves (Brightness-Contrast isn't very good at the ends of the histogram).
As you can see the effect is applied in full on the quay walls, but the shadows in the roofs have also become a bit lighter. Of course it is also a matter of subtlety, you have to be careful to not overdo it. In particular if you use such a mask to boost the dark parts, color shifts occur very fast because a minute difference between two color channels is expanded by the increase of values.
You can use the method expounded in the tutorial to create the masks, but I also have a script with some pre-cooked ones and you can create your own (or use part of the script just to extract a luminosity channel).