I never use full screen mode (or have my windows set to 100%) and I'd prefer having them on the desktop actually.

I move those files quickly and don't want to open folders in the dock. Trust me, I know what's the best workflow for me!
Yes, but:
I have, and that's what I tried before (see my first post), but it didn't work.
What I did was basically go to the Sharing options in the System Preferences, then select a folder (or place, like the Desktop) I'd like to share with my other account. I selected that folder, and added both users to the list of allowed people for this folder. I set them both to "read and write". But it didn't work.

I have no idea why.
Edit:
Okay, it worked, but not the way I actually hoped it would work. I thought if I created a folder on the desktop, it would appear on the desktop of the other account. Instead, I had to go into Users > Name > Desktop to see that new folder. Is there no way to make it act as if it was one desktop?
What about creating other shared folders? Is there a way of doing this? The idea is good, but I would need more of them and in different places.

That would be perfect actually.