Double exposure photography was one of the earliest methods of special effects in photos. It was a surreal effect that could not be seen with the naked eye. It was a complicated process in the past, but today there are plenty of software altering programs than can help you create the effect.
The novelty of double exposure photographs has worn off a bit since we are so accustomed to seeing altered images. But this can be a good thing as well. In order to push your creativity, do what you like and experiment.
I used photoshop to create these double exposure images with bicyclists I photographed in Amsterdam. It was a creative play in matching people with the intent of crafting something meaningful from somewhat ordinary photography.
The first few attempts in double exposure photography may not look great. As with anything new, it’s important not to get discouraged. This technique takes some time to practice and master but the effort will be worth it.