To learn English well you must learn about yourself. You must discover what your own special needs are in English. You should pick out what makes English different from your own language and concentrate on  those parts. And above all, you should pick out your own personal weaknesses in English, pick out your own special problems, find out what mistakes you most often make and make a list of them. It will be best if, in your preparation, you can practise doing all sorts of work that you will be asked to do in examination. You should then make a careful note of any mistakes that you make more than once. Count up how many times you make for each mistake, and the mistake you make most often should be at the top of your list, the next most common in the second place, and so on. For example, if your native language is Japanese, you may find the problem of articles comes at the top of your list. If you speak German, you may find using some of the conjunctions is your biggest problem. If your mother tongue is French, you find you are always having trouble with some of prepositions. And if Italian is your language, you may constantly forget to use a suitable pronoun when you should. But these are only examples of mistakes typical of certain languages. They may or may not be your particular personal mistakes. As I say, these personal ones are the most important of all to discover. .The first item on the list should be the mistake you make  _  .
most often many times more than more very often