The Pomodoro Method is excellent to ensure long-term memory and enforces the little and often idea. In this technique, you study for 25 minutes and take a 5 minutes break and repeat however after 4 sections take a more extended break of about 10-15 minutes. This method is very good for studying but for practicing exam techniques use practice papers online.
In exams, you need to read the question properly, pick out the key information and ensure you aren't missing anything. Many marks get lost because of this silly mistake when you could avoid it by using a couple more seconds.
Being aware of time is important. Stick to the time schedules so that you know how much time is left to finish your questions and you can prioritize the best questions.
If you have the time, to complete every question even if it is wrong, a chance of getting a mark is much better than no chance at all.
Create an extensive vocabulary. This is essential in the test as students with a wider knowledge of subjects get a higher score because some questions in the verbal area are based on the knowledge of words.
Don't overwhelm your child, make sure they get the right amount of sleep, food, and water. This means not too little or too much.
Make sure that before you do all of this, however, that the school you have picked for your child is good for them and you and they have good subjects.