What is the most important tactics in top tier air battle

I’m trying to help my friend get into play the top tier air rb in this game recently. My friend wants me to give him a advise about what should a beginner learn first. Personally I would say that is the notching. I said notching is the core of the top tier but he then said lots of people start shooting each other‘s missiles down without doing notching. So I’d like to know what you think is the most important top tier air battles tactics(and if possible, I’d like to hear suggestions from gaijin’s staff🙏and thanks for everyone who gives me a comment).