Document design and layout are also very important components of technical writing.  :261–286 Technical writers spend large amounts of time ensuring their documents are readable, because a poorly designed document hampers a reader's comprehension. Technical document design stresses proper usage of document design choices like bullet points, font-size, and bold text.  Images, diagrams, and videos are also commonly employed by technical writers because these media can often convey complex information, like a company's annual earnings or a product's design features, far more efficiently than text.  :306–307
This refers to the checking of every aspect of a piece of written work from the content to the layout and is an absolutely necessary part of the writing process. You should acquire the habit of never sending or submitting any piece of written work, from email to course work, without at least one and preferably several processes of proofreading. In addition, it is not possible for you, as the author of a long piece of writing, to proofread accurately yourself; you are too familiar with what you have written and will not spot all the mistakes.