When they go out of fashion, I put them away by storing them in boxes at the bottom of my wardrobe and bring them back out when they eventually they become fashionable again.
When I put them away, I also stuff old socks in the feet which helps keep them dry, this also helps keep them in good shape.
In the picture to the left, the shelves are level. In my cabinet I have the top one level, but the other two I have slanting.
All the shelves are adjustable. For each shelf there are 3 different options at the front and 3 at the back. This means I can have the spaces between the shelves bigger or smaller. I also can use the higher or lower positions at the front or at the back to create a slanting shelf.