I came up with this shoe rack hack when I first discovered IKEA hacking. As a student, I’d habitually drop my (sports) equipment on this extra desk and I wanted to efficiently utilize the space below. As you can see even a standard computer case and simple bin fits below using 1 plank.
IKEA EFFEKTIV desk (discontinued, but this will also work with any desk legs you can clamp around)
Measure the outer dimensions of the desk, including the legs.
Cut a plywood plank according to the size you measured.
Using a hole saw, drill a hole the same size as the desk legs on each corner. Precision work is required here.
Flip the desk over and slide the plywood plank through the legs and let it rest at the bottom (which is the underside of the table top).
Then, measure the height where you wish to place the plank and attach 4 clamp brackets in position.
Finally, flip the desk right side up again and rest the plywood plank on the clamp brackets and your shoe rack is done.
If you have more shoes, I recommend installing 2 planks. Just repeat the steps above for the second plank. Rarely used shoes can be placed at the back. Please note that too high shoes like boots won’t fit using 2 planks, but heels might work out.