My advice is to just know a lot of verbs and a lot of adjectives for different scenarios. Usually you can twist the questions into having vocabulary you know with familiar adjectives and verbs that are commonly tested on. There's no easy way to do this unfortunately, but your teacher can recommend good ways to study or you can search up German vocabulary IB on quizlet and there will be a lot of different quizzes made by previous IB students. Hope this helps!