For compositing in Photoshop I rendered Z-depth channel and Ambient Occlusion map.
In Photoshop, I used Ambient Occlusion layer with “Multiply” blending mode and Zdepth channel with lens blur filter and after these adjustments I did some color correction. For softer and dreamy look of image I take a duplicate layer and blurred it and change the blending mode to “Overlay” take another duplicate layer and again blurred it and change the blending mode “Softlight” adjust the opacity according to look. Here the Final image.
I hope this insight into my workflow has been useful to you in some way. If you have any questions at all, please feel free to drop me an email