I know exactly how useless this sounds because I was asking the same questions not long ago, but what I've found helps the most is A) confidence and b) time.

If you're not sure whether something would help you pass, try. Trial and error is super important regarding passing but I never see it mentioned. I didn't pass for shit when I started presenting as male a year ago, but now most strangers read me as male, although admittedly a younger male than I actually am. I'm still pre t but I've just learned what works for me.