One great aim of revision is to cut out. In the exuberance of composition it is natural to throw in - as one does in speaking - a number of small words that add nothing to meaning but keep up the flow and rhythm of thought. In writing, not only does this surplusage not add to meaning, it subtracts from it. Read and revise, reread and revise, keeping reading and revising until your text seems adequate to your thought.