It depends on the subculture, but it general:
pants chains
band tees
Chokers
Platforms (there are much cheaper ones than demonias)
Boots
Dark clothing
Dark clothing with a few brightly colored/neon accesories
Eyeliner
'Wild hair' (dyed, messy, fluffy, in your face)
Bead cuffs (the bigger the better)
Spikes
Multiple belts on the same outfit
Arm/leg warmers
Fingerless gloves
This is definetly a more mall goth style, and depending on how you u do it scene and emo as well. It's also the style I see most highschoolers wear when they don't have the money/parental approval/general confidence to fully dive into a subculture
This probably isn't the best list, and there's some I'm forgetting, but I hope this helped!