Consider not only what your readers want to know but also what you need to tell them, by way of explanation or example, to ensure that they understand. Omit anything that is irrelevant, and any unnecessary background information. Only students, who may be expected to display their knowledge, should include details that they expect their readers will already know. At work you are not trying to score marks: you are conveying your knowledge to people who require no more information than will satisfy their immediate needs.
Analysing your audience. Find out as much as you can about your readers. Consider their age, education, interests and occupations, so that you can anticipate any difficulties - and their likely response to your message. Some readers may be experts in the subject of your composition. Others, although they are not, may be interested in the possible applications of your work - and be involved in decision-making. Choose words, numbers and illustrations, as appropriate, so that all those for whom any document is intended will understand at first reading at least the parts relevant to their needs.
Designing your message. Your writing should be appropriate to the subject, to the needs of your readers, and to the occasion. Each sentence should convey a whole thought accurately, clearly and as simply as possible, so that your readers take your meaning and always feel at ease. They are most likely to follow your arguments, understand your evidence, and remember your conclusions, if they can relate anything new to their existing knowledge and interests.
Communicating your purpose. Help readers by providing an informative title, and effective headings and sub-headings. Help them to see the connection between sentences, paragraphs and sections. Sometimes a word is enough; sometimes much more explanation is required.