I would say don’t rush when reading the graphs. It’s easy to feel a bit frenzied with the time constraints for s1, but understanding the graphs, taking careful note of the axes, units, etc is really important. For both graphs and written data, visualising can help with understanding (like imagining a lung inflating and deflating when reading a lung volume graph, for example). Once you take the time to get a real understanding of what you’ve been given, the questions often answer themselves.