Welcome to Bored of Studies!
I did not take English Extension 1, so hopefully someone else can provide advice about the subject itself. However, perhaps I could provide some insight into effective note-taking.
It is important that you organise your notes well. You can do this through elements such as good document formatting, colour coding and organising your notes into sections. In terms of the latter, this will allow you to understand your notes better and study them more easily. For example, you may wish to have a heading targeted at techniques (literary and/or visual), and a separate heading targeted at quotes. Of course, the knowledge that you will gain once you start English Extension 1 will allow you to structure your notes according to the content. This applies whether you are taking notes during your classes or outside of class.
Another strategy that can help you when making your notes is to access sample notes, many of which can be found in the
Notes & Resources section. Having a look at good-quality notes made by other students for English Extension 1 (note that this may also apply to your other subjects) can support your thought process as you determine the strengths of such notes and capitalise on those strengths as you create your own notes. Of course, you may also use other students' notes as study material, not just to assist in making your own notes.
I hope this helps!