I find it helpful to make sure I interleave different passages when I'm practicing... rather than drill a problem section for a long block of time, then the next section, and so on, I rotate short passages every 3-5 minutes or so basically at random. I even wrote some software to help me do it (trying to learn The People United Will Never Be Defeated). Also I take more breaks, and have more, shorter practice sessions throughout the day. This technique shows up in research on general teaching and learning as "distributed practice" and "spaced repetition" so I know it's not just me. Has to do with how the brain makes connections and transfers things from short-term to long-term memory. Good luck!