A quick technique tip:
The common mistake that students make in the third octave
is simply overblowing the fingerings one and two octaves lower. The technique
may come more easily this way, but the pitch, response and tone are poor. It
only takes one flutist (or worse yet, piccolo player) in a flute section
playing the overblown fingerings to cause a very annoying pitch problem in the
upper register of an ensemble.
--From "Band Director Talk Shop," Nov. 7, 2017. Adapted from Woodwind Methods: An Essential Resource for Educators, Conductors, and Students by Charles West