When it comes to business writing, one shortcoming I often see is that companies do not standardize on a set of reference guides that everyone must follow. That’s because many people feel all style guides are the same. They are not.
The Associated Press (AP) Stylebook, for example, says to write out numbers one through nine and use numerals for number 10 and above (a real space saver when you are writing newspaper and magazine articles that must fit a fixed number of column inches). The Chicago Manual of Style, however, says to write out numbers one through ninety-nine.
Also the AP Stylebook says the Oxford comma is optional, but The Chicago Manual of Style says to always use it. The AP Stylebook is full of information a journalist would want at his or her fingertips (for example, the difference between murder, homicide and manslaughter) but that a business writer would not.
There are many manuals on the market. If, for instance, you are in the medical industry, you might want to use the AMA Manual of Style.
The bottom line: be consistent throughout your organization. Choose a guide and a dictionary that everyone must use so documents leaving your company are uniform in style.