As someone who is emo a huge part of my closet are jackets... A DIY I would recommend is to get a normal black jacket and add things like studs, safety pins, and spikes. I also like to cut thumb holes into mine as well. All the studs I have used are from old studded belts that have fallen apart, but you can also buy them and spikes on amazon or apparently on https://www.studsandspikes.com/. I haven't used the studs and spikes website since when I did buy spikes I got them from amazon, but I heard its good. Plus, if you do end up buying spikes, studs, or safety pins you can put them on a bunch of other stuff.
I would also go for skinny jeans (they don't have to be super skinny), I find all of mine at thrift stores. They're pretty easy to find, I usually try to find black and ripped ones. You can also find vans there often, which are fun to paint and customize and go well with most things.
Hope this helps a bit! ✿ ʕ •ᴥ•ʔ