Science advances by ruling out incorrect hypotheses rather than immediately zeroing in on the perfect theory. This means that science develops when possibilities are narrowed down to a smaller scale by leaving out incorrect hypotheses. The method is the underpinning of scientific development. How about applying this method to writing?
Writing is a science, a process of getting our ideas across in a clear and logical way. It is hard, if not impossible, to produce a good piece at one time. And the mastery of it invariably comes from extensive reading and endless practice. To make writing easier, we begin by making as little grammatical errors and using concise, specific words. Next, we focus on reasoning skills, to be exact, on rooting out reasoning skills that are not or little used in English. At last, we learn to think about good ideas and proper evidence that backs them up.
A piece of writing often breaks down into three parts.
Part One: Diction or use of words
Part Two: Structure or reasoning
Part Three: Ideas and evidence
Since it is unlikely to write a 'perfect' essay at one time, we have to improve our writing little by little.
Step one: Avoid grammatical errors; use concise, specific words.
Step two: Practice different reasoning skills.
Step three: Think out concrete ideas and back them up with reasonable, reliable examples.
The guideline is that we have to make a draft and then make some revisions to it before we get a designated essay. But remember, this last version of essay is by no means flawless either in its use of words or in its structure and reasoning.