In the photo example I took an image of my daughter and placed her under the sea. I did this because it reminded me of when she used to be inside my tummy swimming around. So I took an existing image of her and an image under the water and meshed them together. I used the three thirds rule and placed her on three thirds of the image to make the picture more appealing.
I also made her a bit transparent so that it would look like she is surrounded by water. I also added fishes in front of her so it could look like she is really swimming with the fishes. I used this photo of her because I thought it would blend her well with the fishes since she’s wearing pink. There’s a lot going on in the photo but you can tell she’s the focal point of the image.