How do you play soft when playing really high?? I've tried but the second octave ones will just start coming out low and the third octave ones go flat. My flute lesson teacher said it has to do with air support and I've tried that. Is there a specific technique to get the soft sounds out?

hm....i think you should play at first really slow in 3rd octave and just with diaphragm and then you go faster. And your tone will be soft and nice in 3rd octave. I allways do this and it helps. Enjoy practising
If it helps...i do it like this...metronome=50---> play with diaphragm in 3rd octave e3-c4 c4-e3 and then metronome=54...58....63....69...

Just pretend you are playing really quiet in band when the band director is talking and you don't want anyone to hear. That is what I do.

Tighten up your embaucher (spelling??) reallytightly and while keeping the velocity of the air the same, make the hole the air is going through (your mouth) smaller. That's what I do when I have notes in the upper octaves that are supposed to be really quiet.

Tighten up your embaucher (spelling??) reallytightly and while keeping the velocity of the air the same, make the hole the air is going through (your mouth) smaller. That's what I do when I have notes in the upper octaves that are supposed to be really quiet.

Micron, my cheeks puff out when I play, but due to relaxation, not a floppy embouchure...