Go through article Mehwish’s Voice Training Guide. While it is primarily aimed at trans feminine training, it does contain the necessary information to be used for trans masculine training as well.

Additionally, watch the following video to learn more about the head resonance mentioned in the Guide above: play_arrow Meta Resonance exercises & lecture by TransVoiceLessons. This is by far the easiest exercise to make someone sound feminine (and, of course, other way around for masculine).

You can find examples of how control of different aspects of your voice sounds in the Selene Archive.

Once you understand the basics, the primary thing you’ll need is consistent practice. Use your voice wherever you can — reading a book out loud, talking in random voice chats, thinking out loud. Get creative.

Feel free to ask for advice in the chat voice training channel.