Here was my first attempt at photographing the stack of can lids:
It was on the floor in front of a big window, and I liked the backlight on the stack and the floor, but the front of the stack was too dark and I wanted you to see more details so that you could tell what it was. It needed some fill light, which just means light that brightens up the shadows without changing the main lighting.
An easy way to make fill light is to use some sort of reflector. I often just hold a plain white piece of paper for fill on something small like this, but in this case, I grabbed a book that was sitting nearby and propped it open to use the white pages inside for my reflector.
Now you can see a white highlight on the side of the stack, which gives it more detail and definition:
Using a reflector for fill light is a simple trick, but it can be very useful when you're using back or side lighting, or have too much contrast on your subject.
I hope you found this illuminating!