Claude Monet said : " No one is an artist unless he carries his picture in his head before painting it, and is sure of his method and composition"
I found this quote by Monet to be significant. Particularly since I have been concerned with light and colour from a scientific point of view and applying this to art. Why significant? Monet is of course a famous impressionist - THE Impressionist - so light and colour should be paramount. Yes they are very important, but I like that Monet's quote also tells us that we must have the design (composition) and method (technique) in mind before we start painting.
It is astonishing to me how important the early stages of the painting process are. The mind picture and the visualisation of how, what and why before paint meets canvas has a profound effect on how a painting progresses. Monet knew that painting light and air would not be enough to carry the painting if his composition was weak.
We can see this even in an atmospheric painting of sea and misty light. How to carry the eye through and around such a scene where the devices of roads, fence posts and treelines are not present to help us compose the painting. Monet composed his paintings in the absence of obvious compositional devices. We can keep this in mind when next we plan a painting. Take risks, but calculated ones.
Once the basics are established then play with light and enjoy the freedom of painting.