Listening comprehension in the German language is particularly difficult because the sentence syntax is completely different to what we would expect in English i.e. the verb goes to the end, commas indicate subordinate clauses, formal German prefers 'Substantivierung' and a 3 min speech could all just be in one sentence! In preparation for listening exams, then, you need to be doing different types of active listening, a little bit every day, so that it's not a surprise on the day. This could look like:
1) Go onto the Tagesschau website (German news channel) and look for 100 Sekunden. This is 100 seconds of headline news at normal speed. This is challenging because they use a formal register, so don't expect to understand every word. Do focus for that minute and a half, try to understand the main topic and message being conveyed (the backdrop picture will help). If you do this every day, you will also learn some common political vocab. e.g. "Brexit EU-Abkommen"...2) Download podcasts from Die Zeit. (available on Spotify). They cover topics like Crime, Science and Technology, Pyschology, Philosophy, Love, Healthy Eating. Podcasts are nicer to listen to because the language used is more colloquial ... usw. Again, don't listen to the full half hour, sit yourself down for 5 mins with paper and pen and see what you can understand. 3) German Rap. The way I got into learning German was by listening to lots of German music and trying to learn the lyrics. Singers like SIDO, Peter Fox, Alligatoah, Von Wegen Lisbeth, speak clearly and use a lot of text in their songs. 4) TV Shows: Der Tatortreiniger (comedy crime-scene cleaner), die Heute Show (political satire, a bit like Mock the Week) Worth taking half an hour a week to sit down to one of these, with subtitles (English is fine, as long as you still focus on the speech and don't get distracted on your phone...)
Happy revising!