As someone who lives in Tokyo, small is the only way you can live. In general, I recommend taking advantage of "dead space" with rolling pieces of furniture. I also suggest using a few big pieces of furniture rather than a bunch of small ones.
Look for "wasted space' in less obvious places. If you have free space above your glasses in your cabinetry, for instance, you can hang items on hooks above them. If your shelves are tall, put in racks to divide the space efficiently. This will help you fit more into the space in a tidy fashion.
I also recommend that you be careful about how you adopt storage solutions. Use baskets, drawers, and bins as effectively as possible. Using the right storage enhancer for the right space can make life mush easier.
I did a few posts on my recommendations at:
Contributed by Shari at myso-calledjapaneselife