As a kid, I pretty much ate books, and I had the good fortune to have several teachers that would just let me quietly read on my own in class while they lectured.
Not everyone has that temperament and ability, but it'd be useful to look at not just the mechanics of learning, but also how to get kids to want to learn. Paraphrasing, don't just teach kids how to multiply--teach to dream of what they can do with math.
Personally, I learn a lot because I know it will often be directly beneficial to me. I don't learn things I don't think will be useful at all.
I suspect many students in middle school and high school find the concepts too remote to apply to their own lives. I think good teachers are able to make the application of knowledge salient and relevant, such that students have a personal incentive to learn it. As an example, I imagine the utility of coupling game theory with learning to work with others (friends even), because this is directly applicable to one's life.