learning how to write is learning how to think. you begin with a problem to solve: how do I express this thought, idea or feeling in a way that best approximates my meaning? what is my meaning? can I refine it? writing is a tool you use to answer these questions.
it follows that good writing will have undergone many revisions. you write, then ask: is that what I really mean? more often than not the answer will be no. so you go back, revise, reread, repeat. if you think it& #39;s easy to write what you mean you& #39;re not aiming high enough.
so IME when a work is & #39;not well-written& #39; (this applies mostly to nonfiction) the flaw lies not in syntax or vocabulary or expression, but in a certain incoherence of thought which manifests itself as poorly framed hypotheses, conclusions that don& #39;t follow from evidence, etc.
good news is this lack is simple (not easy, simple) enough to correct. mindfully read good work. dissect it to see how it delivers. don& #39;t be intimidated, be curious. do it every day until the lessons of those who are so much better than you are part of you. then do it again.