Look at the difference in flow between this image and the next

A simple twist of the camera, and it the photograph has a very different feel

This one is a double photo. The lesson is simple. Sometimes it can be good to rotate your camera 90 degrees, because it can give the image a very different feel. Also, when doing landscapes, especially of valleys and such from above, it can really help the flow of the image if you include some nearby objects in the foreground. It helps give the picture a sense of scale and distance.

Enjoy