It seems to be that a part of the problem for a lot of transwomen is education. Not only must one be aware of such a possibility of learning to speak with a more passable range or register of the voice, but one must also have access to someone who knows HOW to teach someone to put the voice into that appropriate register. It's just like playing the didgeridoo. For decades, I thought that circular breathing (how you keep a trumpet playing for minutes at a time without running out of air) was impossible for the vast majority of people, only possible for those with the "magic" to pull it off. A few years ago, I learned to do circular breathing for didgeridoo, which is essential to play well on this instrument. All it was needed was for someone to show me 3 or 4 things, and once the understanding "click" took place, it was easy from that point on.
Similarly, what is needed is someone who has the ability to help you to remember to do something. That is to relearn how to speak with a preadolescent voice. Remember when you were speaking one day, and suddenly, your voice cracked, and later on, it dropped into a strange lower voice for a few seconds before hopping back into your usual voice? It means that the changes to your voice box was gradual over the few years of growth, but the voice change may not have been gradual as well, but shifted down suddenly. It was shifting up and down uncontrollably. That happened to my older nephew, and I still can hear in my head him struggling with his voice in front of us.
Eventually, you learn how it feels to be in the lower vocal register, and you learn to stay there, soon forgetting how to access the pre-adolescent mode of vocalization. Even though I'm nearly completely deaf, I can access three voices; male, pre-adolescent, and falsetto. You will hear the deaf accent, it might be enough to throw people off my "trans-trail" enough to miss that the voice doesn't sound entirely right.
Between the age of 16 and 19, I think, I was sitting at a restaurant with a friend of mine. We were ordering. He ordered, and then I ordered. Afterwards, he laughed at me and said, "You sounded like a girl!" I was taken aback and thought, "Oh... I didn't realize that!" Apparently, I had slipped back into that voice after a number of years (2-3 years?), probably out of an age-old eagerness to eat a large pizza. I don't recall, though, that I had a cracking voice, but rather, it was gradual.