I notice X posted a month back, how has it been with all this good advice ?
Are you using your belly/diaphragm/Hara ? This is where the real energy for your blow comes from and it is another area for practice. Let your belly fall out, using your muscles to push as you breathe in as deeply as possible, practicing to use your diaphragmatic breathing will give you the reserve when you need to blow strongly and with a steady controlled pressure.
Long notes using all your breath.
Explore your lip posture, have it more like an 'Eeeee' than an 'Oooooo' This will tighten the skin without adding strain.
Also, how long is your flute, you may find a shorter flute easier at this time, or maybe a longer one.
Kel. _________________ The eyes look, the brain sees.