This is not one of those pages.
As a pre-testosterone FtM, I don't pass a lot. Do I mind it? Of course I do! But the idea of trying to "pass" disturbs me for a couple of reasons. Firstly, the very word seems to imply that we are trying to deceive, to pass ourselves off for something which we are not. To say that I am "passing" for a boy implies that I am not, in fact, one, but a woman in men's clothing.
Another problem with "passing" is when it goes too far. For example, I bind my breasts, and wear men's clothes and a men's haircut. That's about as far as I normally go, because it's enough for my comfort level. Everyone is different. Some people have to "pack" or wear fake facial hair, to feel comfortable. Some people (like my wonderful boyfriend) wear feminine shirts and occasionally makeup. But when one starts trying harder to "pass", it creates problems. Is this shirt too feminine/masculine? Can I pull off this one hairstyle I really like, or not? Do these jeans make my hips look too big/too small? Should I try changing my voice? Do I need to change the way I talk to people, or how I walk, or even my facial expressions? You end up overthinking everything, all the time, and you lose yourself in the idea of what you think a man/woman/other should be.
So my advice is, don't try too hard. If you like femmy clothes, wear femmy clothes! If you don't want femmy clothes, don't wear them! If you want short hair, have short hair. If you enjoy your long flowing locks, wear them with pride. Just do what makes you, you. There's no point in escaping one box just to hide in another one. Make your own box, or better yet, just go box-less.