Realise there are limits to how high you can go, eventually you hit a ceiling. In saying that my limit was an E5 after a year on the course, and after 3 years I can sometimes hit a clean A5 now but only during my scales. Work the exercises with a view of consolidation, hit the notes you have now with precision, power and control. Then you'll find range increases almost as a by product. Once you are hitting E5s, the speed with which your range increases slows down quite alot for most people.
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