One of the main projects I had in my guest room renovation was creating a small workspace for myself. By adding a few shelves to a small, shallow closet I was able to create a desk that takes up almost no space!
I don't work from home often, but I'm usually editing photos and searching for inspiration when I'm at home so I needed just enough space to fit my computer and a chair to sit in.
Creating a desk was fairly simple - we added a shelf at desk-height and put some trim around the edges to hide any gaps between the shelf and the walls.
There was already a shelf at the top of the closet so I was able to use that space for storage. I really love the wire magazine holders for our magazines and artbooks, and the chalkboard milk crate is a great stash-all for things that can't neatly stack.