How can I encourage good note-taking?
This answer assumes that the course you are teaching is not about note-taking itself.

Make sure there really is a problem to address

Are the students who you think take bad notes also performing badly in the course? Different students have different ways of taking notes, or even different purposes (for example, I used to write down as much as I could because that would help me learn the content afterwards through "muscle memory").

There is not an unique "correct" way of taking notes. If you know exactly what notes the students are supposed to take, then probably they do not know, so why not provide those notes to them? That would help them much more, and the goal of your course is to transfer knowledge about a specific topic.

If, after considering this, you still want to get the students to learn these note-taking skills, you will probably have to dedicate some lecture time to explain how they should be taking notes. Having them submit some of their notes as an assignment will also help. After all, if it is not part of the course, many students will not be motivated to do it. Keep in mind that students have developed their own learning methods for many years, and changing to a new note-taking method might actually make some students perform worse while they get used to it.