Ppt is generally used now. Anyway, ppt can be copied. You don't need to copy, or just copy those important strange teachers who don't let students take ppt. If a teacher uses ppt, he should focus on what the teacher says. Sometimes the teacher will prompt some important places or his own experiences, which are not in ppt, so remember.
If you write it on the blackboard, I think it depends. Some teachers will write something important, and some teachers will write titles. It's up to you.
My personal habit is to write my notes directly in the textbook without a notebook, so I have no habit of copying definitions. It's important to remember this. If you think copying it can help you remember, good. If you mark important definitions clearly in your textbook with a marker, then you can remember them. I usually mark it with a marker. But it depends on your own habits.
University teachers speak very fast, so many people emphasize preview and review. Of course, it is not easy to stick to it. Personally, I think you should go through it at least twice, which means you should choose at least one of the preview and review after class. If you have time before class, review it first. In fact, book knowledge is something that teachers can understand without telling us. The most important thing is to find out where you are confused, and then concentrate on listening in class. Don't panic if you don't have time to preview before class. Review after class, and study what you don't understand in class. If you really can't, you can ask the teacher. The conflict between taking notes in class has just been said. The point is to listen and keep your notes in mind.
The main content of the notes is supplemented by the teacher (that is, it is not in the book), and the teacher puts forward the key content, because this may be tested in the future (or the teacher didn't say it was the key point, but emphasized it many times), where the teacher is prone to make mistakes, the teacher's experience and so on. In short, the principle is that time is limited, so don't write anything that is in the book or can be tested by ppt.