How should we (a person or group of people) treat you (a transgender person)?
It should be obvious but since the question appears it must not be. I can only speak for myself and I don't assume every person feels the way I do. There is a simple and obvious answer though.
Treat me like a person! I am a person just like you. I have never seen someone ask everyone they meet how they would like to be treated. Common sense and being decent should be the default.
When I hear the question I think the person is asking because they treat women and men differently. Maybe they don't actually but that is what it sounds like.
In my mind the question (for me as a trans woman) is interpreted as: Would you like me to treat you like a woman, who are clearly treated differently by me than men?
Maybe you see a transgender person out and you want to say something? Why? Imaginary person ahead who sees things a certain way.
First, what makes you want to call attention to the person's medical history (here we assume they are seeking HRT for medical transition)? Second, why do you want to make sure the person is uncomfortable immediately by letting them know that you see them different than everyone else?
Even going to someone and telling them how "brave" they are or how good they look is bringing up to that person that you noticed. Most likely they know that people will notice and they wish people would just stop and treat them like everyone else. To you it's a compliment with good intentions but to them it is interpreted as a signal that they aren't accepted.
This might seem a bit too much drama. I mean depending on so many factors, like location, age, and (sadly) how well you pass, the amount of harassment is different for everyone.
For me, I haven't been treated differently in a negative way. If anything people are a little friendlier and it comes across as they see me as an outsider. Some staring or second looks but nothing verbal. Since I don't even come close to passing right now I stand out but I don't care what other's think and I am the happiest I have ever been.
Maybe next year, or the next, or the next it will begin to wear me down. The thing to realize is I will be dealing with it for the rest of my life while I meet new people who will, individually, make the same mistakes. Maybe it will all be different in a few more years but progress is slow and takes effort from everyone. Time will keep moving forward anyways.