At the end of the lecture, ask questions about points that you did not understand.
If the speaker begins to get off topic by telling a story, write it down anyway. Stories help people remember. The story might be related to what you are learning, and may even be on the test.
If it becomes apparent that he or she is trying to stress or emphasize something, be sure to get it down, maybe even a couple times.
Obviously, the teacher/professor will not write down everything he/she says. Listen for key points and important details that are not written down.
When students ask questions, write down the questions and the teacher/professor’s answers. This additional information might answer questions you have as well.
Revise your notes as quickly as possible, preferably immediately after the lecture, since at that time you will still remember a good deal of the lecture. Also it is a good idea to reread your notes within 24 hours of the lecture. It may be a good idea to rewrite or type your notes to make them clearer and more organized.
Revise it with a class mate or two. Two students see and hear more than one. Your notes will have different gaps than that of your class mates.
Review the lecture notes (again) before the next lecture.