If or better yet when, you meet a trans person, regardless of how you personally feel about them, at least show them the same respect you would show for anyone else. That means addressing them by their preferred pro-nouns (he, she, they, them, it) and name (self-explanatory).
It's easy, and it'll make you look like a much better person.
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You see, it's not possible. How am I supposed to know that they're a nonbinary otherkin dragon overlord supergender? That's impossible to know without them telling me first.