It just so happens that any MtF can have a feminine voice with a little work. MtFs get a break with their voice boxes. They're larger than women's voice boxes but the muscles around the voice box are able to contract and make it smaller. All you need to do is to find those muscles and strengthen them.
Try laughing like an old woman or maybe an old witch cackle. You'll feel the muscles around your voice box contract. Those are the muscles you need. They a located around your voice box Now, try using those muscles again but not so strong and say "Hello". Don't worry if you don't get it right away. It's like whistling. Everyone can do it. But first you have to figure out how. The first time I found "my voice" I was shocked! I thought, "who the hell said that?" .... then I lost the voice. The next day when I was experimenting I easily found it again.
Be careful of falsetto. You'll feel that more in the top of your throat. Falsetto vibrates the top edges of the vocal cords. You want to use the entire body of vocal cords. You can raise your voice a couple of octaves but any more and you introduce to much falsetto. Then you'll sound like a man doing a bad imitation of a woman and no one wants that.
After you find the muscles you need you need to strengthen them. You will probably only be able to whisper at first and you'll become sore after a few minutes I strengthened my voice by singing along to Shania Twain during my commute. I tried several female artists but Shania Twain was the one that worked best. I'm not a fan. I don't even like country music all that much. She is simply the artist that worked best for me. You will probably find that a different female artist works for you. Try several. Remember, all you are trying to do is strengthen those muscles. You aren't trying to become a good singer.
While you are working on strengthening your voice you can work on inflection. Remember valley girls? Try talking like them for a while then dial it back for real conversations. It works and I did a little of that but not much. Most of my inflection just came naturally. I still surprise myself sometimes when I say things. Occasionally, I'll utter a phrase an think "Whoa. That was famine sounding.".
I've found that now I can't force myself to make my old male voice. I think it's psychological. In the morning when I first wake up my voice is a bit deeper but it's nothing like before my transition.
