It seems that voice is as different as hair, and what works or did work for me may not work for anyone else

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I'm one of those gals who has to know how something works in order to do it. Going into falsetto and gradually bringing it down just didn't work. And I struggled with every other method until I understood the mechanics.
Importantly, from what I can tell, all methods try and achieve the same thing. So it's all a case of what works is best.
I learned to position my larynx ( long before speech ) through gurgling, which puts everything in the right place. It was all about feeling where things were, and learning to control it without actually gurgling. I literally just did that for months, making strange sounds etc.
With my larynx in the right spot and muscles doing what they need, it's impossible for a male sound to come out. That's when I started to learn everything else ( resonance, speech in terms of intonation and speech patterns, and lots more ). That took months and months with a speech therapist to learn all about resonance, breathing and patterns.
Since, I've not been once mis-gendered or let down by my voice, not once.