I think passing 100% is more a combination of looks, attitude, behavior, body language and overall energy; and not just simply 'looking' female. Pretty much all falls under the "confidence" skill set 😛 If it looks female, walks female, talks female and acts female, it is most likely female.
Being someone who plays a lot of video games, I like to see my passability as an "area of effect" circle on the ground, with me standing in the middle. My goal is simply to shorten the circumference as much as I can because sometimes i get these soul-piercing stares from people who are bordering on offensive/insulting and are most definitely crossing into rudeness territory with zero shame of even being caught. I know sometimes people stare because I'm tall or because they think I "have guts" or on the rare occasion that someone actually thinks I'm attractive, but the energy they give off is significantly different than someone who's staring me down like I'm some kind of zoo animal who broke loose, or some kind of nuclear power plant abomination.. the worst ones are the mothers walking with their toddlers or strollers, giving that look that screams "DEVIANT!". Oh what a world of such civilized people we live in. But yeah, I've taken the idea of my area of effect circle disappearing entirely, out of my head; and simply wish for it to reduce in circumference as much as possible, but my happiness level remains the same. I might exhibit anger or offense to these ingrates being so rude, but it never makes me feel like I'd want to go back because when i think about how it felt to live as an unmistakable cismale, it pales in comparison to how liberating it feels to live as my true female self, regardless of passability. The more time that passes, the less i seem to care about whether others think I pass or not, because when I look in the mirror after getting ready to go out, I think I look beautiful which is more than I can say for my male appearance in the entirety of my short 23 years.