Consider putting a bamboo fence around part of your garden like this one
Find a small stone pagoda like this one
Get a bunch of river rocks like these to surround a bigger stone like this
You might want to add a small water fountain like this
You also might want to create a little flag stone path like this
For another water feature you can grow duckweed in a pot.
Go to your local nursery and ask what types of Japanese plants (trees, shrubs and flowers, and bamboo and grasses) they have that can be successfully grown in a small space.
Korean Grass is one of my favorite things.