Creating a photomontage is an interesting project, here's one that I just finished.
This is a photograph of my grandson Mike Yardley, I like the interesting lighting.
This scene was photographed while vacationing in Lucca, Italy. I felt that it would be a good basis for an interesting photomontage.
I first carefully outlined the photo of Mike and then superimposed it over the photo of the window.
Then I added the red spheres and decided to tilt one of the window panes as if it were dropping, creating a weird scene. I cropped the final image because I felt that the lettering on his shirt was a distraction.