Hmmmmmm.....
I sort of agree. Once they ask the question of whether someone is trans*, they are looking for signs and are more likely to see them. But I think it's actually easier than you make it sound because people are not out there looking. That makes it fairly hard to start the boulder moving.
So unless something is hugely gender incongruent, I think there is more danger in outing yourself by trying too hard that there is by not doing enough to make people see girl everywhere. Trying too hard and seeming unnatural about it is one of the biggest give aways I see. For example, the transwoman who shows up dressed to the nines with jewelry, heavy makeup, and super expensive, fancy, new clothes at an outdoor picnic. She actually looks great in other circumstances. But presenting so strangely in that setting invites scrutiny and makes passing harder.
If you dress to blend in with everyone else and act like you belong, then usually people assume you do belong and they won't pay any attention to you. It's the incongruities and the differences that draw attention.
So the advice is often given to wear more jewelry in hopes of sending a more female signal. But most women wear very little jewelry most of the time. Wearing too much makes you stand out and draw attention. Personally, I wear none at all most of the time, so you won't find those earrings in my ears or those bangles on my wrists.
The advice is often given to wear dresses and skirts to send a more female signal. But most women wear pants most of the time. Personally, I wear mostly skinny jeans this time of the year.
And people are often advised to make sure they never leave the house without makeup on. But most women don't wear much makeup most of the time. Personally, I rarely wear any because in too lazy.
I feel like I'm passing by breaking most of the usual rules trans* people are given about how to pass. And I'm pretty darn confident in my passing. But it's kind of a chicken & egg problem. I don't know if I am able to break the rules because I'm passable or if I'm passable because I break the rules. I don't know if I'm confident because I pass or if I pass because I'm confident.
With that said, I also have to acknowledge that I'm a bit of a freak. I don't usually comment on HRT and passing threads because I'm not sure my opinions or experiences are very helpful to most others due to my own oddities. I am more likely to comment on a suzifrommd thread because I know her offline and I like talking with her.
Your mileage may vary and your experience of passing may depend on lots of other things. So here is my equivalent of Suzi's personal passability assessment.
I do seem to pass pretty much perfectly. To my knowledge, I have never experienced being clocked since I went full time. I have had problems with passing as a trans* person, even in trans* spaces, that have included being called a liar when I come out as trans* and having other trans* people take it on themselves to explain to me what the word "transgender" means. My body looks something like this:
* I'm 5'9" tall.
* I have no idea where my jaw fits in the spectrum.
* I had hip development in puberty and they become more visible when I lose weight. I've gotten teased about my "child bearing hips" since transitioning.
* I am quite small framed.
* I'm carrying too much weight on the small frame.
* I wear women's size 8 1/2 shoes.
* I've never worn a wig. My hair actually is my own hair and I tend to put it in a ponytail most of the time. I sometimes wear it loose in the winter. French twists are great for more formal or dressy occasions.
* I wear contact lenses, but usually don't wear glasses most of the time. I don't know where I fit in the spectrum of brow ridges and such. An FtM-spectrum friend says I don't have much.
* I've never had FFS or a trach shave, so I don't have a scar. But I also don't have a visible Adam's apple and I've had people tell me my face looks like I spent a lot on FFS.
* My voice is a huge passing asset, but I have never had any sort of voice training or vocal surgery.
Hormones seem to affect me quickly, powerfully, and in ways that are supposed to be impossible. My best guess is that since my body produces very little in the way of hormones naturally (like maybe 10% of natural testosterone) and I could never stand more than about 1/4 or 1/3 of "normal" T without flipping out, I just never had a complete puberty. So there was a bunch of puberty stuff that never happened until I transitioned and then it happened in a female direction. That's just me speculating.
But the point is that all this stuff affects my view of the world, and particularly my view of passing. So bear that in mind when considering my advice or opinions on the subject and feel free to discount them if you feel they don't apply.