Ryan Nehal Ramnarain
Peruse the CIE textbooks as many times as possible.
Scrutinise the marking schemes and examiners' reports.
Tailor your answers according to the marking schemes.
When attempting a question, try thinking of ways in which this question could have been further developed. Then, try answering this extension of the question under consideration.
Spot the contents in the CIE textbooks which have been rarely or never mentioned in the past papers and prepare them very carefully.
Peruse as many high-standard academic essays as you can to get an accurate idea of how to write. Reading empowers and facilitates writing. Then, practise as many essay questions as possible and try diversifying the topics that you are attempting. Also, improve your writing speed after you have mastered a broad spectrum of topics.
After reading a particular chapter in the CIE textbook, attempt most, if not all, questions in the classified Chemistry book. Attempt all or most CIE and AQA past papers. The AQA marking schemes, CIE latest marking schemes and CIE examiners' reports are of really high standard. Read them carefully.
After reading a particular chapter in the CIE textbook, attempt most, if not all, questions in the Physics classified book. Attempt all or most CIE, OCR and Pre-University past papers and IB MCQs. Peruse the marking schemes and examiners' reports.
In the marking schemes, scrutinise the method marks, in addition to the final answer marks. Learn the different methods available in the marking schemes that can be used to solve the same problem. This will help you in determining which one suits you the most in terms of time and ease of application in exams.