Social context is circumstances surrounding the story... the situation... what's happening in the society of where the story takes place.
In the case of Tom Brennan, Daniel kills 2 people in a car crash etc.. which results in community backlash and forces the Brennan family to move to Coghill with their grandmother then you can discuss the changes that occur in coghill and how each character 'transitions' I find Kylie is a good character to discuss if you compare her before the move.
Also if you need more help you can visit JC Burke's website and email her with your question, i know she was accepting questions from HSC students. I was lucky enough to have her visit my school and sign me a copy of the novel