I use a new layer and take soft white brush to create some mist at the top left of the rock. Then I lower opacity of this layer to 30% (remember to vary opacity of this brush to get the result below):
I make a new layer (Clipping Mask), change the mode to Overlay 100% and fill with 50% gray:
I use Dodge Tool with Midtones Range and Exposure about 15% to brighten a small part of the left stroke of the rock a little. You can see how I applied this tool with Normal mode and result with Overlay mode:
Isolate the left rock and move it to the left of the picture and make it as a Smart Object and downsize it. I make the top part of it visible:
I add a Curves layer (Clipping Mask) to darken this rock:
I make two new layers (Clipping Mask) and use soft brush with color #7a7e7e to darken the front of this rock that’s hidden from the main light source. I change the mode of these layers to Multiply 80% and 70%:
Create a new layer (Clipping Mask) and use soft brush with color #e9eded to paint on the top left of this rock. I lower opacity of this layer to 20% to create some mist for this part:
Make a new layer (without Clipping Mask) above left rock ones but under the mid rocks. Use soft brush with color #e9eded to paint between the rock ones to make a misty effect there. I lower opacity to 20%:
Open waterfall 1 stock. Extract the waterfall only (I use Channels to do it) and place it at the middle area of mid rocks after converting it to Smart Object and resize it. Flip it horizontally (Edit-Transform-Flip Horizontal):
Add layer mask to remove the right side:
I name this layer “waterfall 1 part 1”.
Copy a part from waterfall stock and position it at the top of waterfall 1. After making it as a Smart Object, I use Warp Tool to bend it:
I use layer mask to remove unnecessary parts and blend this part with part 1:
To change color and darken these layers together, make them selected and hit Cmd/Ctrl+G to make group for them. Change the mode of this group from Pass Through (default group mode) to Normal 100%. Go to New Layer-New Adjustment Layer-Hue/Saturation:
We have result:
Because the mode of this group changed to Normal 100% so these adjustment layers only affect the layers inside this group (waterfall 1 ones).
Extract waterfall 2 and move it to the left rock after flipping it horizontally and use layer mask to remove unwanted parts:
I add two adjustment layers (Hue/Saturation and Curves) to match color and brightness of this waterfall with the rest.
On Curves layer mask, I use soft black brush to erase the top part of the waterfall as it gets light more than the bottom:
Open trees 1 stock. First I remove most of background from the tree using Channels. Then I copy some tree parts to paste into the mid rocks, remember to convert them to Smart Object before resizing:
You can use layer mask to remove unwanted parts.
Make group for these trees as done with waterfall 1. I use a Curves layer to darken and change color these trees as they’re too bright: