To all you trans girls who play online games: be nice to a kid and open about being a trans girl. Help them grind levels, tell them a trick for the enemy they're struggling against, gift them your old gear.
Make a kid associate trans women with that really nice lady who they thought might have been a guy at first. Make them remember the time when they got your pronouns wrong and you corrected them and said it was all good after they apologized when they hear about trans people being belligerent about their pronouns.
A kid who's only personal experience with trans people is that really nice lady will be less likely to fall into anti-trans bigotry. And a kid who knows two trans people and both of them are really nice ladies? They'll always have a seed of doubt when faced with transphobic rhetoric.