Start by assessing your level with an HSK-oriented test. According to your level there will be a certain vocabulary quantity you have to learn, a particular exercise scheme and, of course, different difficulties. So be sure you start your preparation on the right level track.
Take as many mock tests as possible and make sure you are practicing in an mock exam setting: switch off your phone, get in a silent place so you won’t get distracted and allow yourself the same time to answer the questions as you would have at the exam by looking at a watch. Making it as real as possible, you will reach the exam date feeling way more relaxed.
Try a full immersion in the Chinese language by listening to native speakers (if possible), Chinese radio and TV, short videos and listening comprehension exercises. The more you are exposed to the language, the more natural it will feel to be in an exam setting.
Attending a class not only will give you one more chance to practice your listening and speaking, but it will also make it possible for you to solve all your doubts on vocabulary, reading strategy and so on.
Whether it is listening comprehension or writing composition, increase your speed every time you practice your mock test. In order to do so, draw a study plan (you can ask your teacher for help) for you to follow: make sure to include a practice for all the four abilities (listening, reading, writing and speaking) every day and make the most out of it by increasing their speed time by time. By the end of the HSK exam preparation your speed will have increased dramatically!
Following the same study plan we just mentioned, follow your improvements and indicate your strengths and weaknesses. This way you will have a much clearer understanding over the ability you need to focus on.
Do not cram before your test! It is very likely that your knowledge is already set right before the exam. So make sure you get enough sleep, try and do something relaxing the night before exam day so you will feel energetic and ready the next day.
As you have probably already learnt by taking other exams throughout your life, it is very easy to let yourself get carried away by pre-exam anxiety. I can guarantee you that most of the mistakes are made out of distraction and scarse clarity of mind. We want to avoid such a condition that will only take points off our performance. So absolutely try your best to keep calm and stay focused. The chance you waited for sadist so long to show yourself how well-prepared you are is finally there!