A language exam measures a narrow slice of your ability under artificial conditions. That is not a criticism — it is the thing to understand before you plan, because preparing for the exam and improving at the language are two different projects.
Exam technique is worth a level on its own
Knowing the format, the timing and what the markers reward can move your score substantially without your language changing at all. That is not cheating; it is removing a handicap you would otherwise carry into the room. Do at least three full past papers under real time pressure. Most of what goes wrong on the day is pacing, not knowledge.
Find out how the speaking section is scored
Speaking exams usually reward range, fluency and taking initiative — not perfection. Candidates who give short, cautious, correct answers routinely score below candidates who talk more and make mistakes. Prepare structures you can deploy on any topic: comparing, giving an opinion with a reason, speculating, concluding. The examiner is looking for those, whatever the question is.
Write to the rubric, not to your taste
Written tasks have a required structure and length. Elegant prose that ignores the brief scores worse than plain prose that hits every requirement. Learn the expected shape of each task type once, and then you are only supplying content.
The last month is technique; before that, language
Cramming grammar the week before adds very little. Spend the last four weeks on format, timing, and the two or three recurring mistakes your practice papers reveal. Everything earlier than that should be ordinary learning — reading, listening and speaking — because that is what actually raises the ceiling.
Prepare for the exam deliberately and for a short time. If you spend a year doing exam drills, you will have a certificate and a narrower language than you could have had.