Okay, it doesn’t begin with X. But exactitude, or accuracy, is a crucial aspect of business writing:

• Spelling mistakes – Although spellcheckers should never be relied on as the sole way of checking documents, their ubiquity means there is really no excuse for basic spelling errors. Despite this, at the time of writing Google produces nearly 40,000 results for the word ‘inforamtion’
• Grammar (see also Punctuation) – Grammatical errors often end up in documents because of over-reliance on spellcheckers (which ignore an error-ridden sentence like ‘It’s new features empowers the user’. Check grammar and punctuation yourself
• Links and dates – The pesky internet means that online material needs constant attention as time, and other documents, change. This means, for example, checking that links work (either manually or with link-checking software) or making sure that pages are not still advertising a conference that has already happened

Simple errors can destroy your document’s credibility in seconds.