Establish a hierarchical method of indentation to distinguish major topics from minor details on those topics.
Listen closely to the lecture and take notes on the major points using as much shorthand and abbreviation as you are comfortable using.
Fill in minor details below the major topics using your established indentation system to determine where the information should go relative to the major heading.
Revisit your notes with a friend or your book and fill in the remaining small details after the class is over.