Here's my attempt to present to you a method of composing cut out people in architectural visualisations in Adobe Photoshop.
One thing you have to remember is that probably the most crucial element of the whole process is selecting the right entourage. Ideally the photo of the person would be lit in a similar way as your render (indoor, outdoor, studio, overcast, hard shadows, dusk, etc.); a person would be standing on a similar ground (pavement, grass, etc.). I encourage you to take your own photos
There are a few things that are not visible in the video, like shortcuts I use:
Ctrl+J - duplicate a layer or a selected area on top of the original layer
Ctrl+Shift+C - copy all layers in the selected area
Ctrl+mouse click on a layer or mask - make a selection from that layer or mask
If anything else is unclear or you'd like to know something more - let me know.
If you'd like to see people being precomposed in some other light scenarios, please let me know.
If by any chance you liked the video, please let me know :)
PS1. The project depicted can be seen here:
PS. I recommend searching for cut out people on following sites:
great quality, commercial: