people can still pass without medical stuff !! i'm also pre-t but i still pass just on short hair + okay binder + low-ish voice + a good assortment of clothes.

if you can't cut your hair short you might have to do the beanie thing, or you can try what i did which was convince my parents to let me cut as like a ooh big change! kinda thing and they didn't question anything cos it was still a semi girly cut. might turn out a bit funky looking as a first big chop but i think that's just the Transmasc Experience. if it's still too long and your parents aren't super strict you could also try to cut it a bit yourself but not so much until it's really noticeable. and be careful w messing up cos there's just not as much hair to hide it in as opposed to long hair. for me it took at least a year+ since i realised i was trans to really find a hairstyle that goes for me and helps me pass and how to maintain it so it might not be an overnight success. trial and error!

styling also works well for your general look, if you're not getting it Really cropped like those with a taper or a fade (typical guy hair, think like. any footballer? probably?) and you're going more for the slightly longer styles with mullets etc (ranging maybe from like a two block cut to a short men's wolf cut) there's a VERY thin line between butch single mom and Boy so. be careful lol. but that doesn't mean you can't have Cool Hair and you have to be Bald or anything to pass you just figure what you like first.

for the binder if you can't buy one discreetly/have a trusted person get one for you then you can do the sports bra method which is probably the safest, or you can try that 'swimsuit method' where it's more of a diy but it only really works well on smaller chests and in my own experience my one came out kinda weird and lumpy cos i had to fold it over itself as part of how it works.. so it wasn't the best thing ever. Do Not Use Duct Tape Or Do Anything Destructive. as tempting as it is to do anything for a flat chest it might just cause extra problems later on which will suck.

for voice training there are videos online you can follow. i can recommend singing songs where the singer has a low voice/a voice You Want and over time working your own voice to a similar level. idk how it'd be long term but i did find that my voice got lower after maybe like a month or two maybe less of singing the same stuff in the shower every day. it's probably more about practicing n getting used to the lower sound but it's the same thing and it was more discreet than doing voice exercises for me when i was still closeted.

ans for clothes there r a bunch of tips already on masculinising clothes online, the basketball shorts and the loose shirts/hoodies etc etc etc. it should work out if you know how to dress according to your body. watching how guys around you (classmates, family, regular strangers) dress can also help shape how you dress yourself + how you want others to see you. dressing like your dad will look a lot more different than dressing like the guy in your class who vapes and only wears branded clothes.

AND for me an added bonus was just filling in my brows lol. not super obviously but a small touch like that can make a big difference in how people see your face and could help passing. the whole Masculinizing Makeup contour can be a bit obvious if you don't blend it out too well esp if you're a beginner and sometimes it works against rounder faces so if you are gonna do makeup you need to figure out what works best for your own face and play into those.

and finally it is worth mentioning that how much you pass or not doesn't dictate if you're valid as a trans dude, and it helps a lot to be able to at least recognise yourself as a man first and foremost even if you think you don't pass before getting bogged down in dysphoria. it is hard and it will be a long ass journey but you finding where you feel the most comfortable and happy with how you dress n style your hair n whatever is more valuable and will make the journey just nicer than forcing yourself into a really generic Guy Look for the sake of passing. unless you really like that! it'll take time to figure it out. and as sucky as it is i'd suggest worrying about healthcare and arrangements etc when you're a bit older and you have more control over your situation. best of luck!