My mantra is that everything can be viewed as a primary source of the time period, place, and society from which it was created.  This evaluation can take place in a number of ways, and the questions that I have put together to carry out such an investigation are not unique to me.  Below is the form I use and the questions I ask which, when answering them, yield great insights into whatever one is hoping to study:

5. I added this geography question to my list recently, which is strange for me as I feel strongly that one's location and place dictates behavior more than most other factors.  The idea behind this question is to further the information gathered from the questions in box 1; how extensives were trade and communication networks for the people who created the source in the first place?

6. The intended audience can be different from the actual audience.  A motion picture, for example, may have been made with one demographic in mind, but viewed and enjoyed by others.  Plenty of letters make it very clear their intended audience as it usually follows the word "Dear" at the top of the page, but that does not stop someone else, especially much later in time, from reading the words.  

If it is a written document, like a newspaper or book, deciding the intended audience can let us know the level of literacy that existed at the time of its publication.  

7.  The answer(s) to this question are sometimes directly expressed in the source.  A love song, for example, conveys ideas of adoration and affection.  The lyrics are likely very clear about this.  However, beneath the surface of songs, articles, posters, buttons, poetry, legal documents, clothing, etc. etc. is a depiction of the level of free behavior that existed in the source's time and place.  If self-expression and creativity is on display, it demonstrates the behavior of a free person and society.  But if there seems to be a level of conformity or regimentation, then it can imagined that there was some degree of oppression for the person or people responsible for the source.

8.  Nearly all primary sources are at least somewhat prescriptive as well as descriptive, few things are 100% one or the other.  Even snapshot photographs, were are assumed to be unposed, "slice of life" depictions have some prescription to them as the photographer could have captured countless other angles or images besides what was framed in their shot.  All photos are taken for a reason and because the picture-taker intends to do something with it.  Other items are prescriptive because there are only so many uses for them.  Consider a pitcher, for example (this is not a mispelling of "picture").  It could really only be used for two or three things including pouring liquids and decoration.  It's prescribed in its design.  Completely descriptive sources are few and far between and this can inform us of similar ideas as the answers to number 7, and that is that people in free societies tend to be more willing to try and persuade and convince or get people to think a certain way about their position on a topic.