Render does not fit into the sketch. Such a prospect as it may not be in the real world. But the work will not be boring! So I kept it in 2 different scenes and, separately, did render the tower and the magician. Then I glued them in Photoshop. As the lighting I used V-ray light of different colors and HDRI map.
To make the post-processing you need a map ZDepth. But I rendered the scene in 2 files, this depth map, and there were two - to work with the front of the magician and the background to the tower. Connect them was simple - pushed the levels of both cards in different directions to where the middle of the work (in depth), they were gray, cut out the unnecessary part of the front of the card using vray alpha and glued to the background.
In Photoshop, except for color correction, I have added some details. Before you glue the two renders I've put in between different pictures of trees and sky behind. Just added a photo of an engine on a tower on the left for details. After I painted pictures in the right places through the soft light of the same color to the scene.
Magic Bullet photo looks - wonderful Photoshop plug-in for color correction. Separating the work area with ZDepth and Color Range tool, I changed the color in different areas of work. Brushes I painted the right lighting in different modes
normal - the smoke and fog, drawing details
soft light - the shadows and color correction, where I used a photo
linear dodge (add) - volumetric light, the glow
color dodge - a bright glow