Look and listen out for the main idea or ideas of your professor's presentation. Facts are important to take note of, but so are the big picture and points that the professor makes. Facts don't mean anything without supporting a thesis or idea.
In a lecture or class, take notes of the instructor's ideas and points (as fully as possible) in the order they're given. This way, when you refer to these notes later, everything will flow for better reflection and analysis.
Consider organizing and cataloging your notes. You can number your pages in a corner, and leave the first page in your notebook for a table of contents with the class dates and a keyword for the main lesson. If you take notes on a computer or device, name your documents by the date and/or chapter number, followed by the lesson keyword or chapter title. You can even organize them in your MacOS Finder or Windows Explorer folder in sequential order. This isn't just for the perfectionists out there; this can really help you if you tend to be scatterbrained or disorganized.
When you use the Cornell system, you divide your page into sections: cues, notes, and summary. The "notes" section is for writing down the gist of what the professor is saying, important details they say and write on the board, and facts. The "cues" section is usually for after you take your notes during class; it's for questions and comments that help organize the material and indicate areas you still need to examine. The "summary" section is for the big picture; it summarizes what you've learned during that class (or textbook chapter).
If you don't understand something, or want to go back to it later, jot down a question in your notes. This is where the Cornell Note Taking System comes in handy, but you can do this in whatever layout works best for you.
Use shorthand, acronyms, abbreviations, and symbols to take notes faster during class and save page space. You can even make up your own shorthand; just remember to make a key if there's a chance you'll forget your own abbreviations.
Examples: = for equals, Fe for iron, Ex: for example, @ for at, gov. for government, POV for point of view, etc.
Indicate important ideas, vocabulary, and things you're uncertain about. Use a highlighter, underline, asterisk, scribble a star next to something, draw boxes or circles around something, or use a circled question mark to indicate a question or uncertainty.
Leave blank spaces or lines between ideas, especially if you start to zone out or fall behind the lecture. You can try to fill these in later.
After class, review your notes. If you notice any physical or conceptual gaps in information that you remember but didn't record, write/type them in quickly while the lecture is fresh in your mind before you forget.
After class, try transforming your class notes into notes or study guides of your own words— this way, your brain is working hard to comprehend and remember the material. Try converting your class notes into Cornell notes (if you didn't take them this way), a concept map ("mind map"), or a diagram.
Your notes should be doing two things for you: keeping you alert and receptive during classes and lectures, and providing a good source to review for assignments and tests later. If you're still zoning out during class and your notes aren't helping you study later, your note-taking techniques aren't working for you and you need to switch things up. Try any or all of these tips that you haven't yet, and refer to the resources for extra suggestions.