If I’m asked then I say my pronoun is his royal highness.
I call others by their cis gender unless either it’s obvious like wearing a dress or corrected. People can choose how they want to be addressed but shouldn’t expect me to know lol.
One extra note on using they them when you don’t know: No, I’m going to assume that the person is not in the 2% of people that look like one gender and aren’t.