Constructing a pond with a well-planned shape is also important because koi being an active fish will tend to get themselves injured when maneuvering around, thus having rounded curves will avoid all these troubles. Apart from that, there are also few interesting concepts and different new ideas introduced over the years to make the pond look more interesting and unique. For example, a koi pond will never be complete without building a rocky stream or having the falling waterfall as the main focal point and these days enthusiasts also seem to prefer the Japanese bridge & garden theme design as well.
One unique feature which I would definitely recommend and remind a hobbyist not to miss out is the window view side wall which is actually built-in for those who opted for the raised/above ground koi pond. From the picture, you can see that the window view introduces a different perspective and approach to appreciate your pet fish. Rather than looking at your koi from the above, you could also see what they look like below the water level. Having this feature is also a great idea because sometimes you might need to check and look for deformities or injuries sustained on the fish and thus, having this see through fiberglass panel will give you a clearer view.
Other koi related topics:
» Common koi pond filtration system
» What to do with frightened koi fish
» Appreciating the Asagi and Shusui variety
» Selecting the best koi for breeding purposes