A bit of a late response, although I hope your test went well. Your result in your previous test indicates that there are likely areas or specific concepts that you may need to revisit. The problem might be a lack of understanding of particular concepts and/or insufficient practice of questions targeting those concepts. Because of this, you should ask for clarification regarding any concepts you may not fully understand. Once this is addressed, you should attempt a range of questions targeting those concepts (which can be a combination of textbook questions and past exam papers), allowing you to assess your ability to apply your understanding to a range of questions, especially exam-style ones, until you become more confident with those concepts.
The same approach should be adopted with current and upcoming content. This means that you must ensure that you understand all concepts, and seek assistance whenever you face any difficulty. Completing textbook questions can help you determine whether you thoroughly understand the relevant concepts, after which you can complete more challenging textbook questions (if applicable) and past papers in preparation for your upcoming exams. This will enable you to identify and address areas of improvement early on and will make you more prepared overall.
I hope this helps!