'Do up brown' is an idiom that means to do something well or to do it perfectly. If you're wondering what other synonyms can be used for this phrase, there are a few options available such as 'To do something to the nines', 'to do something to the best of your ability' or just 'doing something outstanding'. These phrases signify a level of effort and skill that goes into completing a task, whether it's work-related or personal. Other synonyms that you can use include 'to give it your all', 'to pull out all the stops', or 'to do something right'. Ultimately, whichever synonym you use, the message is the same: to do something exceptionally well.