Photography offers great creative freedom, but there are still many constraints. The most common is the format. Over many, years have been gradually persuaded that the proper format is the set by 45mm roll film: when the digital media arrived, it adopted the same format. Why? Well, we like and it is very handy, and we have become used to it, to the point that any other format looks odd. There is nothing to stop you being different, so why not try?
If you wandered around an art gallery and found all the canvasses were the same format, boredom would soon set in.
You have to start with the standard format, but you have to look at your subject to see the bigger image. Once you see that image it is easy.
The attached image is a simple landscape. The sky is the dominant element, the cloud formation follows the contours of the rocky coast.
The variety of textures on the land forest, grassland, and the cliff with exposed strata provide balance. The hint of blue water confirms the coastal location.
There is always a possibility of "a little extra interest": the gulls on the left add that that little extra.
Once the image is created, the next task is to edit and extract what you had seen in the landscape. This means cropping the picture to bring out what you had seen, and that 9 out of 10 times abandoning the standard format. Don't worry: this simply, photography becoming closer to art, and above all have fun!
There are no rules, just be creative, (hint! and perhaps share them on H2G2).