In order to take better notes, you need to be an “active listener.” This means that you don’t just record what is said. Instead, you should engage with the material and determine the essential elements of what is being said.  For instance, instead of spending time writing down every detail of Theodore Roosevelt's various foreign policy actions, strive to establish key concepts of his overall foreign policy and identify the examples as support.  This way, you have already begun the process of learning and understanding (or, in other words, studying). This necessity of active engagement is one reason why many experts advise against recording lectures.,  If you do insist on recording lectures, or have a legitimate need to do so. Ask the professor beforehand if it’s okay to record. The lecture is considered the professor’s intellectual property. In addition, some institutions have specific policies regarding recording. Don’t waste time easing your way into note-taking mode at the beginning of class.  Be ready to go from the very start.  Lectures often begin with an explicit preview of what will be covered, or at least implicit “leads” about what is to follow.  Listen carefully to the opening of the lecture for context clues that can help your organization and discernment of what will be most important. Don’t pay attention to students who arrive late or who are not yet ready to take notes. Every instructor organizes each lecture into some sort of outline, even if it's implicit and loosely followed. The information that is included on lecture slides will give you a solid idea of how to keep your notes organized. The lecturer will use vocal patterns, hand gestures and other indications to emphasize important parts of the lecture. Start observing these patterns and gestures in order to discern what is essential information..  Recognize main ideas by identifying signal words and phrases that indicate something important is to follow. Your instructor is not going to send up a rocket when she states an important new...

TL;DR in Vietnamese:
Nhớ ghi chú thay vì ghi lại bài giảng. Lắng nghe phần giới thiệu một cách cẩn thận. Chép lại những gì được viết trên bảng. Học cách nắm bắt các tín hiệu và gợi ý của giảng viên. Xây dựng phương pháp tốc ký riêng của bạn. Viết rõ ràng. Dành chỗ trống cho việc ghi chép, chỉnh sửa sau. Chú tâm vào phần kết của bài giảng. Đặt câu hỏi.