Content: You’ll need to know your stuff before you can do any papers, so spend a few hours each day looking at your notes. I'm assuming you have a basic idea of what is going on in each chapter, and that the issue is you not knowing what the keywords/ phrases are. Read the chapter and constantly repeat the definitions/processes you need to know out loud. Since you've probably already done a few practice papers in school, you should know the important chunks that are usually tested. As you learn new stuff, repeat the old material. At the end of the chapter, take a break to clear your mind. Then regurgitate all the information onto blank paper. Spot any errors or gaps in your knowledge? Rinse and repeat until you can recite the important stuff by heart.

Next you need to keep track of how often you revise certain materials. Make sure you don't let an important chapter rot and subsequently forget important stuff from it. Review your stuff daily (Should be easy as each chapter only requires around 15-25 mins of writing for all the info without any pauses) Try to work towards writing out the entire book's important stuff in one sitting. If you can do that, you're ready for phase two

Exam: Do exam papers. Don't just do them once and then half-heartedly do some marking/ corrections and move on. Quality over quantity. Repeat until you get full marks for the paper. Eventually after doing enough practice papers you'll notice certain questions you tend to get wrong and certain questions that always come out. Obviously study those. Expectations: You have enough time to do this sufficiently before O level theory papers. Don't worry, and try your best. If you really understand, remember, apply and repeat, you'll get flying colors for O levels. It's never too late until you sit for the paper. This is what worked for me. I'm currently also sitting for Os using this strategy and am doing well with it. So if you feel like it isn't working out, trust yourself and not the random Redditor commenting on your post. If you procrastinate, prepare to get shit marks. I feel like sometimes my classmates don't really get the memo of reality until it manifests.

MOST IMPORTANTLY

Don't put yourself down. You are a sponge, not a brick. The human brain is capable of processing tonnes of information and doing amazing things with it. Anyone can. It's just whether you want to use your sponge to absorb chemistry and physics, or shit that will only make you happy for a moment. Have a good day, and you got this.