I’m personally a fan of what @mrsdizzyd has done: use wall space.
I’ve always lived in small apartments in large congested cities so the few times I’ve had dedicated spaces they’ve been wall spaces like hers. My favorite was actually a couple shelves I had in the long hallway leading to my apartment door. I effectively took the traditional Catholic church sanctuary and put it up on the wall: A shelf with 6 tall glass pillar candles analogous to the 6 candles on the reredos of a traditional Catholic altar (clear with no images on it so I could print my own on paper and wrap the paper around the candles, and then exchange them for other images depending on the season, or my intention for burning them), a crucifix above that. Two smaller shelves on each side, the left one with a small statue of our Lady and the right one with a small statue of St. Joseph. Since it took up zero floor space it was never in the way, and since it was in the hallway I was forced to pass it multiple times a day, every day. It served as a constant reminder to “pray without ceasing”.
Unfortunately I’m back to a roommate situation (thanks a lot ridiculous, San Francisco rent!) so my prayer corner is no more. My bedroom which is the only private space I have is like a shoebox and the only wall space I could do anything with would be above my bed. I don’t like the idea of shelving over my head while I sleep in a place prone to earthquakes.