ok.
@Juga .. here we go
water up is red, water down is green
Changing brightness, I'm looking at the bright, latest version of the pict, won't fix the problems you have here because you don't understand what you're doing, and you don't understand why the image is flat.
Which is perfectly normal when you're on the path of learning.
Observe light and how it acts in the nature, on the leafs, on the water. observe all sorts of surfaces.. does it reflects? or it's absorbed?
Where does it come from? behind? on the side etc? which direction of the light is giving the depth?
You can experiment with regular objects in your kitchen, you don't need much equipment or money or anything, to understand light, just your eyes.
An apple, pear (fruit with different surfaces) wooden board, knife... etc... set an object on the table, walk around it and observe
Composition is too tight also, allow some room above the waterfall to give us a sense of space
... and I prefer darker version