At my university the professors would record and upload all of their lectures. I would watch the videos at 1.5-2x speed, pausing/jumping back frequently whenev

At my university the professors would record and upload all of their lectures. I would watch the videos at 1.5-2x speed, pausing/jumping back frequently whenever I started to drift off or anything was even slightly confusing, to think it through and ensure that I understood. I got way better comprehension that way. Another trick that worked for me: If there are high-quality lecture notes, download a note, set a timer for the length of the lecture, and aim to read through the entire note within the time period that it took to deliver the lecture. Being on the clock creates a little pressure that helps me focus. It's OK if I don't achieve 100% comprehension; I basically never achieve 100% comprehension during a live lecture anyways. The only problem with these techniques is that it's easy to fall way behind if you don't discipline yourself to consume lectures at about the same rate they're being delivered. Cal Newport's book How to Become a Straight-A Student has good tips like blocking out chunks of time during your week in advance to do study specific topics or do specific assignments.