A style guide is a book that outlines the “rules” necessary to follow for any one kind of writing. These rules may be about simple things like grammar and punctuation, or more substantive questions about citation, layout, or format. Some guides may also speak to style elements such as tone and voice.
Which Should I Use?
Different style guides are used in different fields and genres. Once you begin to produce in one genre, you’ll get accustomed to the requisite style guide, and be able to use it for later assignments. However, it is best to ascertain which guide your client or professor prefers you to use, because there is often a “house style” to be aware of, too.
What’s House Style?
Often a company or a magazine will not agree with certain points of their chosen style, and will establish exceptions. These exceptions may be published as an internal crib sheet, and made available to freelancers after they are assigned work.
Magazines sometimes make the question of style moot, as a copyeditor will tweak your copy to the preferred style or internal house style. In this case, simply polish your writing to a shine, and don’t worry too much about the nitty-gritty rules.