The first thing you can do to improve your note taking is to make sure that you have read the assigned materials and come well prepared to class. If there are any questions you have about the readings or things you did not understand, make a question sheet for yourself, and fill in the answers if the instructor discusses them or ask the instructor (or your tutorial leader) during the questions session at the end of class (or after class).
Next, review your notes carefully after class and correct any parts that seem illegible or hard to follow why the material is fresh in your mind. You might also want to cross-reference between your notes and the textbook, and use colored highlighters to indicate specific types of materials (e.g. dates, themes, etc.) If there are gaps in your notes or points you didn't quite follow, contact your fellow students or instructor for clarification so that you have good notes from which to study.