In South Africa in particular, a lot of our high school education is rote learning.
Unlike other tests, the GMAT is testing your abilities and not your knowledge. You are given a very short space of time for each question because you are rewarded for finding clever strategies to answer questions.
Understanding what the GMAT is, and what it tests, is your first step in designing an effective study plan. Make sure you are not wasting your time and effort on the wrong strategies.
You can think of preparing for the GMAT like training for a marathon. You are building up your ability over time to do your best on the day.
Just like training for a marathon, you want to keep your practice consistent and avoid losing momentum by stopping and starting.