How can I organize shoes and boots in the garage.

Try using white wire shoe racks that you find in the Storage section of the big box hardware stores. They are slanted to hold shoes/boots and as you mount them to your wall you can set the right height for tall and short boots.

https://www.pinterest.com/pin/381891243387913334/

Im using the crates for the shoes, and sealed totes for the boots. Tall boots have to be placed lying on her side for storage in the crates.

Caution -know the climate change is in the garage can cause deterioration and dry rot in these shoes and boots. I’ve lost Northface and L.L. Bean boots this way. It doesn’t always snow enough to require boots in my area. At one time a certain retailer had a lifetime guarantee and would replace them- not any longer. I have a new unworn pair I need to remove the garage because of this new policy. These boots are 2-3 seasons old and have never been worn!

Another possibility is to use a trouser type clip hangers for boots and maybe put them on a rod suspended on the wall?

https://www.hometalk.com/diy/organize/garage/easy-diy-garage-shelving-8957576?r=1

Here is an article that might help - https://www.thespruce.com/garage-shoe-storage-1398292

The only boots we keep in the garage are the snow boots we use when we have to clean the snow off the driveway and sidewalks. It gets too hot and humid in the garage in the summer for other shoes and boots, especially if they are expensive boots. I use the plastic shoe boxes for shoes, some heals don't fit, so I use some a little larger. I use the smaller underbed boxes for boots so they can lay flat and not be folded over. The winter boots we keep in the garage are put in a cardboard box that is open so that the humidity can dissipate . The only other shoes that are in the garage are my garden tennis shoes and they come in for the winter, I don't want to find a furry friend nest in them in the spring when I go to use them.