I’ve been doing this for a while. All I’ve concluded is that there is no one right way, but there are plenty of mistakes you can make. Here are some don’ts and do’s.
Don’t assume the reaction you get is genuine. People are mostly going to tell you what you want to hear, and that’s true for other things too. Even if a girlfriends new doo shocks me a little I say something nice so she knows I noticed and I care. In the long run you’ll know how they really feel by what they do.
Don’t tell them in a group. You rob the minority who actually want to be honest about their feelings or have questions from expressing themselves.
Don’t supply details unless asked. This subject can be very touchy, especially for men. Men can be very homophobic, and telling them about anything, I mean anything related to HRT, SRS, body changes, just don’t.
Don’t ask them questions, let them volunteer their feelings. If you press them either they’ll lie to protect you or themselves or you’re going to hear something rude.
Give simple answers to questions and understand they have just found out you’re trans, they probably know next to nothing on the subject. Do offer to answer questions then or any time after.
Last, no matter what, try not to be too disappointed when the reality of your actual transition causes some of them to turn away. There are a ton of reasons for this and really, none of them are your fault.