In the listening exam, what do I do if I don't understand anything that is said?

First of all, don't panic! You may think that you didn't understand the whole piece, but are there any parts you did understand? Look at the possible answers if it's multiple choice and apply the process of elimination- if there are any you can rule out, do so! A bit of common sense never goes a miss, so even if you manage to reduce your options by half, it means you can take a more educated guess. If you still have a second listen, work on picking up the details and see if there are any more you can rule out, or if you pick up any more details. If it's not a multiple choice question, and you have no idea, it's better to have an educated guess at something if you can pick out any key words in the question- do these trigger any memories from your textbook and/or classes? Think back to those vocabulary tests throughout the year, and see if you can make any links!