Hello Zain and welcome back.
This is a very busy composition with a lot going on. For me, the repetitive nature of the "Heart" trees and the floating islands is not working. The clouds opacity's are inconstant making some look like clouds and other like cloud shaped fog. The trees in the foreground have been poorly selected from their original image but it actually works for this image lending itself to an "other worldly" feel. I get the Avatar reference, but the waterfalls do not look natural, again they look like some of the clouds, and appear too transparent. I'm not certain if you have a huge floating glass sphere in the sky or a distant orbiting planet with a uniform surface. There are some light rays coming in from the upper right hand side that for some reason come to a complete stop right above the mountain peak. I do enjoy the color scheme, the green grass on the floaters is complementary.
All in all, not a bad comp. A little more planning and plenty of practice.