Between Time and Space

First of all, I feel part of what you are portraying here: a lone figure, sifting sands in the desert.
I don't see the spirituality in the figure, although performing an endless task repeatedly might be a
spiritual journey in itself.

Technically there are a few areas that you could improve on.
First, the gradual red to blue sky could be more blurrier, or more blended by a larger soft brush.
That would make it recede to the background more and give you those beautiful red/purple/blue hues.
Also the sky around the sun should be more blended. I would maybe even drop the sun slightly
behind the horizon, to indicate it's distance.

I feel the figure could be a little more off centre to make for a more interesting composition.
I would place it a little more to the left, so that (in my western culture anyway) I would be reading
even more sand to the right.

Also you could add some texture to the sand in the foreground. Especially a palette knife might be useful here.
That way, you increase the variety in textures and get some more detail in the foreground which increases the depth
in the painting. Also I would add a shadow of the figure, that would be cast because of the sun.