Much of what the teacher teaches is given in the form of a lecture. In lectures, it is generally important to take notes so that you can later repeat and deepen the material on your own. However, you also have to learn how to take notes properly, because it's about noting down essential points and not missing what the teacher says while you're taking notes.

Every teacher has a certain rhythm, a pattern in which he speaks and teaches. This rhythm, once you get to know it, tells you when the teacher is going to change a subject and in which direction his lecture will lead. This rhythm should determine the structure of the notes so that they can be followed later. A change of topic should be made clear in the notes with a line or a new heading.
Often the teacher follows the structure of the textbook, which makes it easier to recall what has been taught later. If the teacher mentions book references, you should write down page numbers.

Handouts distributed by the teacher in class can make note-taking much easier. There is no point in repeating the information on the slip in the notes, rather the notes should refer to the slip as a reminder.
It is often useful to make notes directly on the distributed pieces of paper and build on their information content.

Information that the teacher writes on the board is considered a guideline for the structure of the notes. Basically, everything written on the board should be copied into the notebook.

Learning material that is unclear should also be noted down in order to ask the teacher for clarification later. Unknown technical terms should be written down so that they can be looked up later.

The notes should be organised in such a way that they harmonise with the lesson. Occasionally it happens that a lecture has no real structure, but seems to jump from one thought to another. In this case, take notes in groups so that the individual trains of thought can be connected later.

To save time, notes are only ever listed in key words. Many terms can be abbreviated, but of course only in such a way that they can still be deciphered later.