Lauren, is there any chance of finding a voice therapist? I believe some decent ones are online now, I don't know how effective that is. I would also suggest maybe buying Melanie Phillips or Andrea James CD. Do you have a decent ($60 - $80) voice recorder that plugs into your computer so you can practice and download your practice sessions in chronological order. I remember when I was pre-transition just crying over my voice thinking "NOTHING IS CHANGING!!!" It takes a lot of practice and determination for some people. The important thing is that you don't give up. Obviously voice is super important to you. Find models of voice for you, hear the way they speak, mimic it, practice getting to know your mouth, nose, vocal chords, etc. Make funny sounds. You also need a good spectrograph to analyze your voice for pitch and quality levels, which are small parts of speech but important, nevertheless. 190 -225 is where you want to be with lots of range. (sorry this is choppy thoughts, I'm just throwing stuff out there) Go online and search Harvard Sentences." There are about 200 of them and they are specifically developed to practice all the different parts of the english language. It's an awesome practice tool. If you are not yet full-time there is only so much you can do for your voice. If you are going back and forth between boy voice and girl voice, you won't be able to stay in just one for long, they will blend together.
I think one of the big, big things is making sure you are out to people and then asking them to work with you and give you advice. If they think you sound different, ask them how you are sounding. I remember going from boy voice to girl voice my brother would say "dude, you sound GAY" and I knew it was taking a few hours to go back to boy voice. It isn't just pitch, it's inflection and how you say words. That is hard to just flick a switch and change I think.
So don't get frustrated! Practice 10-15 minutes a day. The hardest thing about voice is that no one really can give you detailed instructions on how to do it so that it works for everyone. You will hear yourself, ESPECIALLY if recorded, and think 'omg, I sound so dumb, I'm done with this, NO MORE!" but you have to work through that! There is light at the end of the tunnel. Think of what you have riding on making this work! You can do it

Meghan