During our Photoshop tutorial, we were taught how to simulate levitation. The basic concept behind it is that you have to take 2 images from exactly the same position and angle with the same settings, one of the background and one of the "levitating" person sitting on something.
Once uploaded onto Photoshop, the first step is to past the person image on top of the background image, ensuring that they line up perfectly.
Then using the erase tool, the stool and its shadow is carefully erased from the person image, with the background image coming through. This lines up perfectly with the top image, so the difference isn't noticeable.
Finally any final touches can be applied, such as the image's brightness and contrast.
The final image produced shows the person levitating above the floor, all from just a basic Photoshop edit.