You have improved quit a lot, but youre biggest problem is youre out of shape renders and stocks. Remember to hold shift down when you resize.
Youre renders could be blended better as well, try to place some textures in front of the render as well. Add some lightning work onto youre backgrounds as well. Make a new layer, take a white soft brush, add some spots with it, and put the layer on focal point, mask or soft light - maybe lower the opacity as well.
Keep practising mate
