Your writing should be readily understandable. Clarity of writing usually follows clarity of thought. So think what you want to say, then say it as simply as possible. Keep in mind George Orwell’s six elementary rules (“Politics and the English Language”, 1946):
Readers are primarily interested in what you have to say. By the way in which you say it you may encourage them either to read on or to give up. If you want them to read on:
Do not be stuffy. “To write a genuine, familiar or truly English style”, said Hazlitt, “is to write as anyone would speak in common conversation who had a thorough command or choice of words or who could discourse with ease, force and perspicuity setting aside all pedantic and oratorical flourishes.”
Use the language of everyday speech, not that of spokesmen, lawyers or bureaucrats (so prefer let to permit, people to persons, buy to purchase, colleague to peer, way out toexit, present to gift, rich to wealthy, show to demonstrate, break to violate). Pomposity and long-windedness tend to obscure meaning, or reveal the lack of it: strip them away in favour of plain words.
Do not be hectoring or arrogant. Those who disagree with you are not necessarily stupid orinsane. Nobody needs to be described as silly: let your analysis show that he is. When you express opinions, do not simply make assertions. The aim is not just to tell readers what you think, but to persuade them; if you use arguments, reasoning and evidence, you may succeed. Go easy on the oughts and shoulds.
Do not be too pleased with yourself. Don’t boast of your own cleverness by telling readers that you correctly predicted something or that you have a scoop. You are more likely to bore or irritate them than to impress them.
Do not be too chatty. Surprise, surprise is more irritating than informative. So is Ho, hoand, in the middle of a sentence, wait for it, etc.
Do not be too didactic. If too many sentences begin Compare, Consider, Expect,Imagine, Look at, Note, Prepare for, Remember or Take, readers will think they are reading a textbook (or, indeed, a style book). This may not be the way to persuade them to renew their subscriptions.
Do your best to be lucid (“I see but one rule: to be clear”, Stendhal). Simple sentences help. Keep complicated constructions and gimmicks to a minimum, if necessary by remembering the New Yorker‘s comment: “Backward ran the sentences until reeled the mind.”