Avoid using abbreviations and acronyms if you possibly can. Don’t use them in public information materials. Your readers don’t want to keep having to check what an acronym stands for, plus capital letters are always harder to read.
Not: 90 kg
But: 90 kilograms
The exceptions are acronyms that have become part of the culture, such as the RCMP, CBC, MLA.
In conformance with popular usage, we are dropping the periods in the acronyms a.m. and p.m., which are short for the latin "ante meridiem" and "post meridiem".
Not: The meeting will take place at 9 p.m.
But: The meeting will take place at 9 pm.
Write provinces, territories and countries in full if you can. If you do use abbreviations, don’t use periods.
Not: N.W.T., B.C., P.E.I., U.S., U.K.
But: the NWT, BC, PEI, the US, the UK
Rather than use an acronym for a department or branch, use the name in full, such as “the Yukon Mineral Exploration Program” or “Health and Social Services” and then after that just write “the program” or “the department”.
If you feel you must use an acronym, make sure you write the name in full first and then immediately write the acronym in brackets afterwards. For example, “the Communications Review Committee (CRC)…” If you find you need to use several acronyms, include them in a glossary and put the glossary at the beginning of your document, not at the end. Make it as easy as possible for your readers to understand what you have written.