The best way to be an ally is to listen with an open mind to transgender people speaking for themselves. Talk to transgender people in your community. Check out books, films, YouTube channels, and trans blogs to find out more about transgender people and the issues people within the community face.
from Tips for Allies of Transgender People by GLADD
See also PFLAG’s Straight For Equality Guide To Being a Trans Ally, and the additional resources linked from both sites, for more information on how to level-up your allyship in these disappointing, enraging times.