Back in the late 80s, I experimented with double-exposure photography. With my trusty Minolta X-700, I would shoot one photo and slowly crank the advance lever while holding the rewind release button. And I would cross my fingers that the film didn't move or tear.
It was an exercise in trial and error. Sometimes, the exposure wouldn't be right; other times, the composition would be off. And sometimes, the film would slip as I cranked the lever and would end up with overlapped images.
Here is one of my first successful double exposures. You can tell this photo was composed in the late 80s because the Daly Building is still standing next to the Chateau Laurier. That night, the moon was actually rising about 90° or more to the right of this shot. Also, I had zoomed up on the moon to make it appear bigger than it actually was. (But not too much, because I didn't want overlap.)
I haven't experimented with double-exposure photography in a while. I wonder how my D-SLR would handle doing this?