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 sad anything that is avoidably ugly?
But you are not obliged to go to all this trouble. You can shirk it by simply throwing your mind open and letting the ready-made phrases come crowding in. They will construct your sentences for you – even think your thoughts for you… and at need they will perform the important service of partially concealing your meaning even from yourself.
From the essay Politics and the English Language, By George Orwell