Hi Mari,
How is it going? Three weeks ago was the last time we talked. I missed you a lot.You mentioned something which makes you anxious in the letter.With your request, I am gonna give you some tips, some advice that I use in every exam.
You revise the topics before exams, but what is the most suitable way for you to learn?
Learning has many techniques from Pomodoro to pictures,graphs. You should find that you can understand better than others.T do some reading after every day, lessons to keep the information in my mind easier.
You always feel nervous, you can easily overcome this situation.I listen to music before tests to concentrate and relax.What makes you relaxed?Just don’t be panic, it is not more important than you all.
During the exams, there are some rules that you must obey.You should read all of them carefully and pay attention during the exam time. For instance if the calculator is not allowed, you don’t need to bring it.
You can overcome every obstacles, but you should be relax to face them. Find the way which fits you and write me about your studying technique.
See you soon honey,
Elif 
