A lot depends on the instructor. The good ones go slow enough that you can both follow along and take notes. What worked best for me is to pay attention when p

A lot depends on the instructor. The good ones go slow enough that you can both follow along and take notes. What worked best for me is to pay attention when professor is explaining and quickly write down in my words the explained concept- like moving it from my RAM to SSD. This way I build about 80% understanding of the concept. Further redoing the notes by referencing material/problem solving took me closer to full understanding.