That rule being, “Always keep a foreground rock handy”. Rocks and their commonplace use in the foregrounds of photos has been a staple foodstuff in my photographic recipe book for a long time. It never fails to draw oooh’s and aaaaah’s from all those who recognise a piece of quality photographic work. Rocks in the foreground. I love them.
(I’m going to hold a ‘rocking up your foreground’ weekend course in 2009. Those interested should apply within.)