Possibly the last time you got any help with writing was at school or university, where your aim was to impress people with your knowledge and intellect; but business writing has a different purpose – it is mainly about sharing information.
Writing is a reduced form of communication – you have to supply enough information without overwhelming readers with detail. And you have to get the tone right without anyone seeing your gestures or hearing your tone of voice.
Readers are busy people too. Your new operating manual requires their attention at the same time as emails, phone calls and meetings – how will you ensure your written communication gets read and actioned before they get distracted?