Paul's quite right – it's normal to follow the term in full by the abbreviation the first time you use it, or in a lengthy document the first time in each chapter. To make the task manageable, perhaps you should write the document using just the abbreviations. When it's ready to publish, search for strings of three or more upper-case letters [or two or more, depending on your text] and put in the full terms by hand. You could also prepare for this by keeping a list of terms and abbreviations.