This is kind of an easy one. I honestly can't believe I haven't tried it until now. This works best in an uncluttered room, which I do not have. So, I used someone else's space.
What you need: a tripod, an empty room, a model, and a chair/stool. I didn't have my tripod with me at the time, so I used a large plastic container. I took a shot of the empty room then another of me in an awkward position on the chair.
In Photoshop, I opened my two files and placed the model and chair image over the empty room image. Then, I erased the chair. Seriously, nothing to it. When you try this, the light and shadow of the room may need to be adjusted in the photos. I also added a touch of a shadow on the floor with the Burn tool.
Here's another variation of the shot:
