Go through the syllabus and practice as many past paper questions as you can. Basic knowledge of accounting standards tested in P2 is needed for P7. At least try to solve 5 recent attempts by writing and in exam like conditions. Then compare your answer with examiner's suggested answer and marking scheme. This will help you in identifying and correcting your mistakes.
This article is very helpful in tackling Professional level exams:
How to tackle exams - a marker's perspective
Also don't ignore professional marks.
Hope this will help you :)