Says George Orwell:
A scrupulous writer, in every sentence that he writes, will ask himself at least four questions, thus:
- What am I trying to say?
- What words will express it?
- What image or idiom will make it clearer?
- Is this image fresh enough to have an effect?
And he will probably ask himself two more:
- Could I put it more shortly
- Have I said anything that is avoidably ugly?
See also: George Orwell at Encyclopedia Britannica.