I feel that conversation number 76 of Rav Nahman [Breslov] is not known well enough or understood well enough. In it he recommends learning fast, and specifically emphasizes that this applies even if one does not understand. while he was referring to learning through the two Talmuds, Midrash and Shulchan Aruch in this way, I think it applies just a much to Mathematics and Physics.
The actual statement goes like this ''אין צריכים בלימוד רק האמירה לבד לומר הדברים כסדר וממילא יבין ואם אינו מבין בתחילה יבין אחר כך ואם אע''פ כן לא יכול להבין כוונתו מה בכך? כי מעלת ריבוי הלימוד עולה על הכל "One needs in learning only to say the words in order and automatically he will understand, and if he does not understand at first, he will understand afterwards. And if even after that he does not understand, so what? For the greatness of a lot of learning goes above everything."
[Read to the end of that conversation and you will see that Rav Nahman meant this with review;--but that is to get to the end of the book one is learning and then go back to the beginning. I think review four times is the minimum amount.
Learning in depth is also brought there in conversation 76, and in terms of Gemara I think the best in depth approach is to learn the Avi Ezri of Rav Shach. However any of the basic achronim will work also--i.e. the Chidushei of Reb Chaim of Brisk or his two disciples Shimon Shkopf or the Birschat Shmuel.
