Here’s some videos I found and they may be good for some Ideas for you,

Take a look and see if it will spark any idea for your garden…

Interesting the way they had placed the sitting area near the pond and waterfall, the main concern you would have is keeping an eye on any children you might have or have visiting, it does however provide a beautiful atmosphere for entertaining.

Here’s some videos with ideas for Town house garden designs from a Co. in America. some of the ideas are good and can be adapted for any long but narrow block.

And here’s another with some good points to consider….

He talks about procedure with drainage and irrigation etc.