For the SAC itself, you should be reading and re-reading the questions for the Listening Test so that you are really, really familiar with what you are being asked about. You get to hear the Listening material twice so you should be matching the material with the questions and the second run-through should be confirming these points and perhaps allowing you to add more detail to your answers. I think more practice should give you more confidence - the ABC has stacks of podcasts of different lengths that you can listen to, pause and take notes. Maybe you've already done this, maybe you can work with a classmate to listen to some examples, then repeat what you've heard (commenting on similar aspects to the listening test on the 2017 exam). Questions about "language and delivery" are asking you to identify something like "tone" and a quote to verify this.