The first rule is to identify early because it is important to know/remember what the item is, but perhaps just as important is to identify thoroughly. Capture key identifying details.
Off-Off-Broadway productions come in an endless variety and key details can vary wildly from one production to another. So, having a standard set of identifiers that apply to all productions is not practical. However, if you start with the 5 W's of Research you're sure to cover your foundational bases.
WHAT is the item
WHAT was the title of the production
WHO was involved (WHO were the principal members of the production team and/or WHO completed this work and/or WHO is in this photograph?)
WHERE was this production performed
WHEN was this production performed
and if appropriate
WHY and/or HOW, which includes additional pertinent information about the item or production such as if it was the second play in a series or if it was a co-production with another company or that the set was constructed entirely of rubber bands.
Capturing this information at the outset is instrumental for organizing and later on, searching and retrieving information from your archive.
TIP: For each production, create labels with the fundamental details of the production that are distributed to all departments with instructions to affix them to all production artifacts.
Note: You should give thought to the kind of preservation materials you use. For example, acid-free labels and envelopes are available at most office supply stores.