I'm not a CIE student. Was back as an IGCSE student but shifted to Edexcel in A Levels. In general, I can say that it varies from person to person on how he/she studies and what is the best way for them to study. What I did was that I had gone through Youtube videos of the topics according to my specification, read from more than one source(both internet and books) and then of course, prepare notes and practice questions based on that topic(not past papers!) and then hit the papers. That way, you can be able to face different questions without way too much difficulty.