While that approach really helped, at a certain point I hit a wall where I needed to hear what I actually sounded like. You can't tell what you actually sound like without external help, and a program that can play your voice back to you can help you get outside of your head. I found Voice Tools to be a great app for my needs, but any halfway decent audio mixing program like Audacity can work if you just keep rerecording over the same clip (I don't actually recommend Audacity, that was just an example of the type of program you can use). It will be unpleasant hearing you own voice, but it certainly beats having someone else critique it for you.

Thankfully, all the practice I did before allowed me to get through that phase in only a couple weeks. From there, I moved on to using my voice full time, which was more of a mental challenge than a technical one. I found that I often slipped back into a masc voice whenever I wasn't actively concentrating, as my brain defaulted to it whenever I was in front of people. That took another few weeks of being very mindful to not use any other voice, regardless of the context.

Eventually, my femme voice became the default, which is why I malefailed before starting HRT. I needed to travel through deeply conservative areas at the time, and I figured I would be safer if I boymoded. However, after a month of using a femme voice full time, I could no longer use my masc voice in front of others. Combined with my long hair and very sparse facial hair, multiple people gendered me as female despite my best efforts. At that point, I gave up on ever boymoding again.

While I do kinda miss being able to do a masc voice, especially for singing, the dysphoria keeps me from learning to do both. I don't even know for certain what I used to sound like.