As an exam approaches, it is very easy to end up thinking: I do not know what to study, everything looks familiar, I will just start the book again.
The trap in that approach is that most of us gravitate to the questions we already know and already get right. The result is that your score hovers where it was, the parts you did not know remain unknown, and all those study hours buy you very little.
So you need a way of tracking progress. Keep it simple. The simpler the better.
Three colours
List every question type or chapter in the book, and mark each one:
Red (Low). Questions you cannot do. Read the answer straight away, work out why you were wrong, and read around it until you genuinely understand.
Amber (Medium). Questions you half know. You could explain forty or fifty percent of the approach but cannot get to the final answer. This also covers questions you can do but which take far too long.
Green (High). Questions you know thoroughly. For anything involving calculation, your response has to be fast. Green means it is properly yours.
Most of your study time goes on turning Red into Amber, then Amber into Green.
A few rules
Once you have marked something Red or Amber, you may only come back to see whether it has moved up after at least 24 hours.
Note the date you attempted it, and review it within two days at most so it does not fade.
Do not avoid the Red ones. These are the questions that actually make you better, even though working through them feels thoroughly demoralising.
Only mark something Green when you could explain it clearly enough for a non-specialist to understand what the question is asking.
Be careful about promoting things. A page full of green feels reassuring, but it is false comfort if you have not genuinely improved.
Why this works
The method rests on spaced repetition, applying something measurable to tracking your study. After you take in new information, your brain gradually discards it unless you revisit it.
The everyday version of this is meeting someone at a wedding, talking happily for hours, and being unable to recall their name a fortnight later.