For the steps, add a slight lip at the top of each tread, this will add a visual break due to the shadow it casts. It will also add a small amount of visual complexity.
In terms of composition, I have two thoughts, one - move the figure off center a bit more (say, to the right) and lower the camera to almost the floor and aim a bit more up past the figure. The second is to raise the camera up above the figure a ways and look down at the upraised pose.
For the waterfall textures, try elongating the vertical component of the mat to give more a sense of the flow.
Just some ideas I had, hope they help - you have a really good idea here IMHO.

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