For me, it takes multiple passes too, but their quality varies significantly depending on how familiar I'm with the subject. If the subject is challenging and t

For me, it takes multiple passes too, but their quality varies significantly depending on how familiar I'm with the subject. If the subject is challenging and truly new to me, my approach is more or less like this: On the first pass, try to understand as much as possible, but don't push too hard if I hit a road block. It's OK to not fully understand or be hazy on key details after the first pass. Then take a break, and ideally work on something else, sometimes for a for a day or two, until I feel ready to take another pass. Also, go for walks or watch a movie or do something else that takes my mind off the subject. Try to explain things to myself, to get a sense of which things I don't really understand. On each subsequent pass, spend time only on those things I don't really understand -- until my little brain gets tired or I hit another road block. Then take another break, and ideally work on something else, until I feel ready to tackle again. Again, go for walks or watch a movie or do something else that takes my mind off the subject Try to explain things to myself, to get a sense of which things I don't really understand. Keep doing passes like this this until I can explain everything to myself because I fully understand it. Throughout, I look for and rely on informal explanations, friendly tutorials, video lectures, and other auxiliary materials that can be readily found on the Web. Also, try to replicate experiments, do exercises, and/or write code if and when applicable. My approach is best described as "long-term persistence."