Practice papers are a good way to experience the type of questions you could be asked in your real exams. Therefore I highly recommend it but when you are looking at the mark scheme, understand what you did wrong and try to improve it. For an example, if your problem is not reading the question properly, to improve this, you could learn how to underline key points in the questions. This could be printing out random questions (it doesn’t have to be about the subject) and underlining important information in the question. By continuously underlining and focusing on the key points in these random questions, you will be able to answer questions and understand what the question is telling you to do.