I suspect there are no 'rules', though nothing is exempt these days from fashion or fashionable formula. Perhaps start from the other end.

This is a fantastic country for walking as there is such a variety of scenery and light, often within short spans of time and distance. Yesterday I went to London by train and the blossom against the spring grass and water was breathtaking over the Chilterns and Thames valley, transforming a usually boring journey, even on a dull overcast day. No camera, nothing to bring back.

The challenge is to find a way of portraying and sharing the outdoors...by trying to get something of the space and breadth into a rectangular frame. Some things just work and some don't. Letting the mind auto-run on the frame and what it might contain helps. So does digital as one can bin the failures with nowt lost.