Be aware of emphatic cues during the class. Filter out distractions and noise. Pay attention to your instructor not your classmates. Anticipate questions before class and listen for answers. Review syllabus, reading and homework before class.
Record notes immediately.
Write something down even if you don't understand the concept. Include examples given by instructors and leave space for later additions and corrections. Review your notes immediately. Stay after class for a few minutes to review your lecture notes and fill in what you have missed. Discussing notes with a few classmates may help jog your memory.