In my early days of going out as a woman, I was very concerned that little things about how I dressed would give me away as a man in a dress. Now, with a lot of experience out in the outside world, I realize that that "yes, there are unspoken rules to learn. But, no, they are not always meant to be followed."
Being presentable as a woman is an art. One has to learn many unspoken rules about dressing, such as the use of accessories, jewelry, and shoes. For example, if one is wearing a high neck dress, a woman would often wear a necklace that breaks up the monotony, and adds a splash of color to the palette that stretches down to her breasts (and sometimes beyond).
I can't imagine this woman's outfit being worn with anything else but a necklace such as this.... But being authentic also involves knowing how much flexibility one has in obeying/breaking the unwritten rules. So it is important to always observe other people and examine their appearance for what does and doesn't work for them - if only to figure out what those rules are.
There are many kinds of authenticity. I work on my presentation, as I want to blend in as much as possible. If you look at the cropped view of my face, you can see my masculine face with a little bit of effort.
The face without the glasses and the wig looks masculine. Even with this, if you focus on my lower jaw line, it implies masculinity. Thanks to make up and other feminine cues, I am accepted as a female for purposes of socialization. But some M2F transgender people don't bother much. They are comfortable with receding hairlines, masculine faces which could be feminized with facial surgery, and voices that don't sound feminine. (No, this is not a criticism, as it is an acknowledgement of the differences in effort people are willing to expend to reach a satisfactory endpoint.) I am not comfortable with my weight, but have to accept it for now, as well as the size 28w dress that I wear with it....
I also strive for authenticity in the way I speak, as well as the subjects I talk about. So you'll rarely hear me talk about sports when I'm in female mode - unless the woman I'm with wants to talk about her daughter's soccer team. The same thing goes for most things that are typically male in nature, which will include tools, cars, and other things that relate to a man having status in his "tribe" - unless it is a woman complaining about her man (or complimenting him) for some belief or behavior. Ideally, I'd like to pass for someone's grandmother - even if I'm babysitting someone else's children.
Somewhere, I think there is a limit to how authentic one can be. Are we playing roles? Or, are we just trying to be our real selves? I can never be sure at times, as sometimes, being authentic is something we learn to be, and not something we are already. And in a way, this is part of the the equation that both defines who and what I am...