I find it helps to not go the route of, "Jill identifies as Jack now", but rather try to see that person as Jack. Don't try to fix the words so much as your concept of who they are; add an extra step in your identification process of, "if they identify a particular way, just go with that".
You follow "Doctor Who" at all? There's a Matt Smith quote that applies, but then you might call me a nerd and being a nerd wasn't cool when I was growing up.