The best step is a simple, "What pronouns do you prefer?" or "What are your preferred pronouns?"

A big thing language wise, is to steer clear of gendered language in speaking with groups. Saying things like "Ladies and Gentlemen" or "Boys and girls" can be really exclusive of non-binary and genderqueer people.

Also this goes without saying but steer clear of any slurs too. The "T" slur being a big one there. But also avoid saying things like "genderspecials" or "gendertrenders" or "gender-benders."

Communication is a big thing in knowing what transgender and non-binary people need from you. Know that there is a wide spectrum of pronouns. Some are very specific to the person, as gender is a very personal experience that varies among people.

The most common non-binary or genderqueer pronouns you will hear will probably be "ze/zem/zer", "they/them/their", and "xe/xym/xyr". And make sure to defend a persons pronouns should they be challenged by another person.

If someone misgenders a trans person you are working with, and they are openly trans/non-binary/genderqueer, help them socially transition and make sure everyone uses that persons preferred pronouns. And on the other hand, if they are not openly trans, do not out them to anyone. Know the person you're working with. Communicate and know their needs above all. That's the best thing you can do. Give them respect, comfort, reassurance, and if necessary, space.