I will just start with something brief. One technique that I had adopted for SPM was studying in subtopics. I won't spend much time doing too much in one day, probably 30 minutes-1 hour , as I would like to completely master the subject in small sections. Then, I will just skim through a few specimen questions on the topic to get a whole picture of the topic and its important areas. 10 minutes before I sleep, I usually do some brief reading on the topic again.
In school, teachers have to report their progress in their lessons to their panel heads every Friday. At home, I record what I have done in a week. At the beginning of the year, prepare a planner for completing the syllabus as if you are doing self-studying at home. Then, your work will be more spread out and organised.
In school, I used to have a study group in which we designate different subjects' 'assignments' to different members. Biweekly, we have a comprehensive worksheet of the topic which was taught in school during that period of time. We wouldn't have specific answers. We just sit down, share our views and our methods of approaching the question and collectively, work out the best possible way to answer the worksheet's questions.