I got full marks last year and included things like:
-When it was written
-The status of the person writing it and the significance (woman in 1600s, unusual etc)
-The reception it may have had at the time/now.
-Any references to current affairs at the time (Henry VIII by Shakespeare/Fletcher was written to appease pro-Elizabeth audiences, The Rover by Aphra Behn was considered to have references to Charles II)
I tried to include these things throughout the piece rather than just a paragraph at the beginning. For example, one of the questions was on 'They flee from me that sometime did me seek', Wyatt and I talked about how at the time he was writing short-lived sexual relationships and the idea of courtly love were prominent, as well as his potential link with Anne Boleyn...
Does that help?