Write the first instance out in full, with the abbreviation in brackets. Then use the abbreviation for all other instances on the page.

Examples:
Abbreviations, such as Doctor (Dr), or London Drive (London Dr).

Acronyms such as for your information (FYI).

Initialisms, such as Her Majesty's Revenue and Customs (HMRC). 

‍‍This is an accessibility guideline, meeting Success Criterion 3.1.4 Abbreviations, level AAA.