If you have any scrap 2x4s laying around, use them to help organize. Any shelf that has many products on it that are about the same size. Stack three 2x4s in the back, then stack 2 directly in front of them, than 1 in front. Now you have 4 heights to work with. Shortest items could go in the back or least used or you could make rows of certain kinds. So many options. I'll have more examples after we move (we plan to move soon).
In this before photo, you can't see the duplicate items.
In this after photo you can now see the duplicate items.
Depending on the items you have a 2x2 could also work well.