These are not necessarily to do with your voice, but are to do with “passing”.
If the people that you meet are unsure of your gender they are likely to either ignore or abuse you. Your enemy here is gender ambiguity. Generally if you give enough cues to people to nudge them in the “female” direction, they will accept it and address you as such.
Top tip 1
Choosing your name. Not many people get to choose their own name. It is a bit like being your own parent! The best names to choose are unambiguously female names. You don’t need to be called Crystal or Fifi Trixibelle (though of course you can if you like!), Sarah or Jane are just fine, but Jo and Sam are ambiguous and don’t give enough cues to people to nudge them in the direction you want.
Top tip 2
Answering the phone and making calls. With your new gender obvious name always start a phone conversation with “Hello, it’s Sarah (Jane or Crystal!). This works both if you are making a call, or answering the phone and again, gives a useful cue. On the telephone people can’t see you, and your voice and name is all they have to go on.
Top Tip 3
Clothes. You don’t need to wear a skirt or dress all the time, and it’s not all about frills and flowers. Look around you, few women do. But be careful of presenting as androgynous.
Some “new” women can also get a bit giddy and go through almost an adolescent phase as the hormones and relief at finally getting going on their journey kick in.
Again, look around you. What sort of style do you like? Look in magazines
Top Tip 4
Those little touches. Though some people have to wear heavy makeup, some are lucky not to. If you are in this position I suggest that you still use a little lippy and/or eye makeup and some jewellery. Again it is a visual cue to nudge.