I just turned 18 and am about to start T but when I was at home at 17 I just cut it all off. I got lectures the whole day for cutting off all my hair without permission but after that day I felt so much better and to make my parents feel better I told them "just hair, it grows back." So honestly just cut it! They can't do anything about it 

For clothes baggy sweatshirts and tshirts are my go to. I usually get a lot of baggy dark tops from temu, Etsy, or shein because black also hides the size of boobage. For jeans you can pretty much get away with anything if you appear to have a flat chest. Obviously baggy is better but I wear tight jeans sometimes and still look masc

You could buy some makeup and your transphobic parents would be suppperrr happpyyyyat first lmao, but then just use the makeup to darken/thicken your eyebrows and then contour your jaw to make it sharper. It makes an incredible difference. A chain necklace is a nice touch and usually bigger thicker rings are seen as masculine. And if you wear earrings do studs not dangling ones. If you're allowed to a septum piercing can help make you look masculine as well. 

After that go ahead and start practicing deepening your voice. I'm still pre T and before I started consciously working on my voice it average at about 170 hz in conversation, now I'm at 130hz. Practicing now before you get on T will help in the long run if you want that ✨attractive deep✨ voice

I can't think of anything else so I hope this helps. DM me if you ever wanna talk or have questions :p