The last step of an image for me is post-production, using photo editing software, in this particular case Photoshop. There are two important things for me in this part of the process. I think post production is very important in the image making work flow, because it enables us to be more individual and lets us add a unique defined style to our work, allowing us to differentiate our design creations from others (in case we want to achieve that of course!). Also keep in mind the result we want to achieve with our image as we begin and have yourself a target set if the end result is not expected.
In the following collection of different Photoshop screenshots I show the steps I used for editing the images for both the day scene and night scene. Also the different channels (Render Elements) used from the rendering (Depth of Field, Ambient Occlusion, etc.).
With the inclusion of rendering channels in my work flow, I chose to add these two in particular, because they are the ones that help me better define surfaces or edges (ambient occlusion) and different depths in the same scene (Z-depth for depth of field).
As for the Ambient Occlusion, I could have configured it directly in the scene but by also making it separately and then mounting it in Photoshop, you achieve much better results and better control.
With the Depth of Field you could blur it with brushes and Photoshop Blur, but the results are not always optimal and set it in the scene for rendering greatly increases render times.