So you're searching for goth prom dresses and you aren't entirely sure what you should choose. After all, it can be difficult to decide what you want your dress to look like and also what accessories that you should choose to go with your prom dress.
First of all, you need to understand that the gothic subculture is not only about expressing yourself, but it is also characterized by dark colors mixed with deep, bright hues. Red and black is a very popular combination but you could also choose black and blue and black and green. Black and yellow is not a very common combination, but if you like it, then go for it! It's up to you what you want your prom dresses to look like!
Short dresses are not very common as far as prom dresses go, but you can also choose between romantic, Victorian style dresses, or you can choose dresses that are very grungy, shredded and dark. It's up to you what you would prefer. Keep in mind that some things may not be allowed. For example, you probably don't want to have a dress that is completely ripped up. However, you could consider choosing a dress that is ripped up and then putting a whole one underneath. You might want to add a studded belt or a sash or something else that you feel will complement the dress. It's up to you what this is.