If your school requires that you bring a laptop to school every day, then it's fairly convenient for you to take notes during class time. What I do is whenever the teacher is speaking or demonstrating something that I believe is or will be of value to me, then I make a note of it with however much detail I feel necessary. At this point, the most important thing is to keep up with the teacher, so it's fine if your notes aren't impeccable the first time - it's sufficient to ensure they are comprehensible by you so that you can later refine them when you have time (after school, free periods), where you can then organise them as you feel comfortable.
So when you initially come across the information, I would jot down the essential points; remember not to leave out anything you feel important, and as as quality can always be improved later on while you may forget the main ideas, the main ideas > quality
This applies to any kind of information, worksheets could be invaluable sources of information, as well as diagrams and even random google searches on the internet to clarify things.
If you bring exercise books to school instead, the process is the same, bar the higher efficiency, so it becomes even more crucial that you take in the main ideas and not mind the quality too much.
