I own a lot of shoes. Lots. I love them all. I wear them all. I just have a LOT!
This is how I was organizing my shoes. Don't judge. (Or judge to yourself. I don't want to hear it.)
I measured the width of the existing shelves and invested in six tension rods that fit the inside dimensions of the shelves.
This is how it turned out.
If I do it again:
I have room for another "shelf" under the bottom shelf. I should have bought an additional two rods so that I can put my sandals out. For now, they will stay in a basket until summer.