Any tips on writing gothic literature?
So there is a yes and no to this. The traditional scholarship does not remark gothic as a genre, but as a literary "mode" that changes with time. So it is a really flexible thing leading to genres like gothic romance or gothic horror. Some of the hallmarks though of the gothic genre include the past exerting an influence over the present, anxious characters (particularly in regards to the future), the supernatural (in English traditions, not the American where the antagonist forces as immaterial concepts), and isolating environments.
Some of my personal takes on the gothic though involve uncanny environments, critiques of our world (gothic horror in the 21st century seems to center on critiques of neoliberal capitalism, with tinges of the supernatural and shady characters. For me and the gothic pieces, I write it is more about creating an environment as the gothic literature on here is kinda a unique type of micro/flash-fiction.
TL;DR Gothic changes with time, but creating anxiety-inducing environments, uncanny characters, degrading mental states, and locations, and strong influences of the past are good elements of gothic literature (esp. gothic horror).