As with all subcultures you should research them!!

Read gothic books (Frankenstein, Dracula, anything by Edgar Allan Poe)

Listen to the music!
Here are some bands to get you started:

-The smiths (morrissey is a shit person though, you can research that)
-Human Tetris
-Joy Division
-The Cure
-Molchat Doma (they are a russian band)
-Lebanon Hanover
-London After Midnight
-Selofan
-Boy Harsher
-Rosegarden Funeral Party
-Depeche Mode
-New Order
-Bauhaus
-The Sisters of Mercy
-TRAITRS
-She past Away
-Drab Majesty
-Merciful Nuns
-Talking Heads
-Vision Video
-The Agnes Circle

movies:
-lost boys
-beetle juice
-dracula (the one with bela lugosi)
-the addams family (the tv show)

Clothing:
Again thrifting is good for getting clothing.

ethic nu-goth clothing: https://www.marywyattlondon.com

platforms (you can also buy this brand on amazon): https://demoniacult.com

Emily Boo on youtube has a lot of hauls and recommends good brands

spirit halloween lmao