I can see why the testing system that you find in school is important to some degree. You do not want unqualified people teaching Physics or other subjects. On the other hand, tests can be frustrating and can discourage people. 

My feeling is that everyone can learn Physics and Mathematics, but not everyone can be a physics professor. 

The first thing one needs is the idea that it is important to learn, even for one that is not particularly talented.  Why is it important? Mainly you see this in חובות לבבות ומעלות המידות ומורה נבוכים Obligations of the Hearts, Greatness of Good Character, and the Guide for the Perplexed.

[Ibn Pakuda, Binyamin the doctor, and Rambam/Maimonides.] In particular the Rambam spells it out in the Guide in the parable of the country of the king at the end of vol. III or vol. IV [I forget which].

The next thing one needs is to say the words and go on from beginning to end. That type of fast learning is brought in Gemara, and Ways of the Righteous, and also Rav Nahman of Breslov brings it in Conversations of Rav Nahman 76.

Then the next thing is review. But I have not figured out about review if there is any one method. Myself I go back page by page. But review might have other methods.