Many people across the Known World have written articles, created templates, and otherwise provided resources for people learning how to document. Here are just a few of them.
An Approach to Documentation by Mistress Ailis ingen Mheadhbha.
Notes from a class on doing research and documentation before making the physical item.
Arts and Sciences Documentation Questionnaire by Antonia di Lorenzo
A series of straightforward questions designed to produce a reasonably thorough piece of documentation.
Finally, Drachenwald’s A&S judging criteria for specific crafts might help you think through additional things you might want to discuss, based on your A&S area.