Thank you for the question 🙂 I did Physics, Math and Japanese HL, and Chemistry, Geography, and English B as SL.
It’s not like I was a good student, and I struggled a lot in school and university. I think I was able to achieve it because I found out what I am good at and which study method works for me.
I have analytical skills that allow me to think on the spot, but I am terrible at memorization apart from the geolocational and visual memory. When I studied for an exam, I made post-it notes which had equations/facts on it, and I put it up on a wall. When I answer a practise question, I only allow myself to look at the information that is on the wall. If some information is missing, then I make post-it note and add it to the wall.
I keep revising the post-it note on the wall, and at the end, there are only information that are essential to you on the wall. Two days before the exam, I remember everything on the wall by associating the information to the position on the paper.
This worked for me. It’s not for everyone, and it’s a very slow learning process (got to start 3 months before the exams). So, I just try hard to compensate for my bad memory using methods that I can rely on.