Example by CAndiFLA
With the emergence of Yotube, the “self-help” transgender voice lesson has become a popular tool for transgender voice training. Here is an example by CAndiFLA, a very talented youtube performer, who produced a series of instructional videos.
(And, again, some additional examples.)
And, finally, if you wish to browse for some context/background information, you might want to look at this informative website of speech-language pathologist Christie Block