When taking notes, you should listen for the professor's main points and note the evidence that he or she gives to support those points. Review your notes regularly, preferably after each class. If you review your notes while the class is fresh in your mind, it will be easier for you to notice places where the notes are unclear. Mark these places and clarify confusing points as soon as possible, either by researching the issue yourself or by asking your professor. Refer to your syllabus throughout the semester.
Many professors provide detailed syllabi that state the themes for each section of the course.
Use this as a guide for your own studying and thinking about the course material. Take careful notes on the material you are reading for the course. Keep in mind that simply copying long sections from your texts is not very useful in ensuring that you have understood the material. It will be much more useful for you to take notes in the form of summaries. If one is not assigned for the course, consider keeping an academic journal.