It’s all about how you look at things. Finding similarities isn’t about making things look the same. More often than not, it’s about finding the qualities that make very different things work well together.
Find images that are similar when looked at one way, but different when looked at from another point of view.
Here’s one idea to get you started:
Take a photo yourself, then take another picture of something completely different, and find a way to make them look like they belong together. You can also do this using a web image search. When you’ve found a set you like, upload them to the site.