Set the values of this layer as indicated in the screenshot.
Give this layer another new adjustment layer with a clipping mask. This time choose color balance and set the values as the one below.
Then we need to add some highlights to the upper edges of the rock. To do this, create a new layer (Shift+Ctrl+N) with a clipping mask. Take a very soft round brush set to about 30 px size at 20% opacity. With the color of #c3dbe8, paint the edges of the rock to give them some highlight.
Do color adjustment layers to the second rock. Firstly give it a hue/saturation layer with the same values as the one used for the first one. Then give the second rock brightness/contrast adjustment layer with values indicated below.
Finally, give the second rock color balance adjustment layer with the same values used for the first rock. Here is the result:
Proceed to give color adjustment layers to the left rock layer. Give these new adjustment layers clipping masks. Make sure to position the layers above the texture layers within the left rock folder. Here are the adjustment layers to be given:
Make sure to hide the effect of the brightness/contrast layer by masking on some areas as pointed by red arrows. This will bring back the original brightness of the image. The areas are parts where the moonlight is supposed to be more casted. So we should reveal them.
Finally, create a new layer (Shift+Ctrl+N) with a clipping mask. On this layer, paint soft dark blue color on lower areas around the left rock.
With the same techniques, set color adjustment to the right rock.
Mask the brightness/contrast layer on areas pointed by red arrows.
Finally, give the color balance layer with the same values used in the left rock. Here is the result:
Do the same ways to set color adjustments to the caves or tunnels. After that, create a new layer with a clipping mask. On this layer, paint some white lines around the tunnel and some dark blue color inside it.
In the next following steps, we still set color adjustments to the other objects in the scene. What we do here is just repeating techniques we did in previous steps. We just apply three adjustment layers to the other objects as we have done to the previous objects. Play around at hue/saturation, brightness/contrast, and color balance to find the desired result of each object. Here is what I did for the rock in front of the left rock.
Do the same ways to the waterfalls.
And finally here is the result after setting color adjustments to the bridge and castle. Just play around at the three adjustment layers mentioned before. Make sure to give a clipping mask for each.
Now we will set overall color and mode for the entire scene. To do this purpose, make sure the adjustment layers we are going to create are placed in the topmost position in the document. Go to layer > adjustment layer > selective colors. Set the values as given in the screenshot. Set this layer to normal at about 15-20% opacity.
Give another adjustment layer: gradient map. Set this layer to normal at 100% opacity.
Here is the result so far.
As we can see, the gradient map layer has made the scene a bit darker. We should hide the effect of this layer a bit to certain areas around the moon and sky, top of the left rock, waterfall and right rock, and anywhere else where needed.