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I compose shots I take and edit by first identifying the focal point in the shot which is the "punchline" at the end of the story where I want the eye of the viewer to come to rest initially and keep coming back to. A key factor in that eye movement dynamic is contrast. What contrasts most — tone, color, sharpness, relative size, etc. — will tend to demand more attention from the viewer.
After identifying my focal point I zoom in tight on it, literally, mentally, or by create a frame with my fingers and slowly expand the frame, moving the focal point around in it. I'll try the four "thirds" nodes, centered top, centered bottom. One of those six compositional "sweet" spots usually work. If not it's a clue the final result probably will not be very good. There are exceptions, but landscape shots usually look more balanced when they are either 2/3 foreground and 1/3 sky or the opposite because it provides a clue to the viewer which is the more important content they should go look at. Also in a landscape the eye will seek out details, searching for the answer of what was so interesting that you stopped to take the shot. That's why it helps to have a destination in mine for them before raising camera to eye.
The logical focal point for your shot is the the origin of the waterfall. It contrasts well but the problem is the sky contrasts even more as the crop expands upward. But how important it the sky to the overall story in this shot of the waterfall. Not much I think. So the simplest solution is to crop it out. You might not be able to do that at capture but you are not constrained by the 3:2 proportions of the camera...
Cropping down and eliminating the sky gives it a more panoramic feeling and but to my eye gave it an unbalanced look because their is a lot of detail on the right side of the creek but a big boring rock on the left. Again the simplest way to eliminate boredom / distractions is to edit it out with the crop...
In addition to the crop I did some tonal adjustments, keeping them as simple as possible:
1) Opening the image in Levels I moved the middle slider right, lightening all the midtones
2) Then I burned the edges of the frame to darken then back to where they were.
The net effect is to make the central focal point areas of the photo lighter. That's actually closer to how you would typically see the scene than the camera records because in person the pupils of the eyes dilate when concentrating on detail hidden in shadows.
Another difference in seeing by eye and what the camera captures is that the brain filters what the eyes are seeing, "tunneling" in its concentration on a very narrow 2° arc in the center of vision and tuning out the rest until something on the edges which moves or contrasts some other way attracts attention. That "tunneling" of concentration can be mimicked in PP by blurring the edges or any content in the photo you want the viewer to pass over en route to the more important things you keep sharp. Below I re-visited the first crop but blurred the boring right side, left edge and top to send a subliminal clue to the viewer to pass over it. I've exaggerated it here more than I normally would so it is easier to see.
The final perceptual tricks are the rule, sampled from the leaves, and black mat. In photos we are conditioned to equate tone with shadow detail. Surrounding a dark background shot with a 0,0,0 black border will make the shadows of the photo, by comparison, seem like they have more detail because they are lighting. This is due the way our brains adapt on the fly to contrast and color balance. The color of the rule sends a subliminal clue that color is somehow important, which triggers the brain to look for and notice it more.
The entire photographic process is just a combination of perceptual magic tricks starting with the "big con" of convincing the viewer the 2D photo is a real 3D scene. Magic works by knowing what the audience expects to see then using that knowledge to manipulate what they notice. Taking the photo is like the empty hat seen at at the beginning. Post processing is where the hat gets switched and the white bunny jumps out. Here it's a white waterfall.