According to the US National Archives, "Document analysis is the first step in working with primary sources."
The worksheets linked below help ask pointed questions in examining different kinds of historical or primary source documents.
They follow this general progression:
Meet the document.
Observe its parts.
Try to make sense of it.
Use it as historical evidence.
The worksheets were created with younger learners in mind, but they serve as a simple guide to getting the most out of a primary source as possible for anyone not already very familiar with working with them.