how to compare Dracula and A Picture of Dorian Gray within the theme of the gothic

i'm so lost in the comparison between these completely different novels

They are not that different.

First of all, look at the sort of characteristics you have in Gothic texts. Here are five things:

1. Isolated setting (Dracula's castle vs. Dorian's estate/mansion). All these settings come together to emphasize the necessity of evil

2. Supernatural entities (Vampire (Dracula) vs ghost/spirit (Dorian's painting)). Could relate this to Victorian values and superstitions.

3. The Gothic "double" (Van Helsing and Dracula [clash between rational and the irrational] and Dorian and the Painting [the division between body and soul]). Maybe focus on internal and external realities of both novels.

4. The confrontation of religion (Dracula [Catholicism] is the figurative Ant-Christ who promises eternal life through the indigestion of human blood, symbolisng the blood of Christ. Then, Dorian Gray [aestheticism of Catholicism through his description of the Priest's robes and of the Church]. You can look at how Henry serves to be a figurative for religion and the corruption religion can do (Henry gives Dorian a philosophical book and corrupts Dorian). Could also tie this in with science(knowledge)/religion,

5. Eroticism (Dracula and Lucy/Mina) and then homoeroticism with Basil and Dorian.

Now, if these are any of your interest, pick one or two and then get to work!

I love these two novels, they're amazing!