I personally suggest adding comedic misunderstandings reguardless of your genre. As long as it makes sense with the flow and tone of the story, small comedic moments can often add to it.
Some of these could include:
If she has powers she needs to learn how to use them. Lots of things could go pretty horribly wrong there and her struggling to figure this out will seem more realistic than “and then she suddenly had complete mastery over all her new found abilities.”
A similar idea to that of before, she has to learn to deal with any down sides. If you’re going for classics such as sunlight burning her, garlic aversion/allergy, etc. There are several things she could forget or things that could go wrong here along with several ways she could mess up.
I’m assuming vampires probably have some customs or social expectations humans don’t. A simple misunderstanding could end up pretty enjoyable reguardless of how it’s played.
My other reccomendation is basically where I think any issues may arise, I highly suggest making points of differences between vampires and humans and having the MC struggle with some of these.
Not everything has to be a struggle, but if some things are it adds just that little bit more of depth.
I also reccomend you consider how she would do mentally with all of this. My main grudge from vampire things is that they tend to take themselves too serious at all times, have the MC just easily figure everything out, and have the MC be completely mentally ok with everything.
I think that the idea of her being homesick is great and also something to consider is if her morals are at all brought into question as she’s now a vampire.
I think the main thing to do is simply:
Recognize that your character will struggle with some things, add depth, and think about how things would affect her.
Also a general world suggestion is giving vampires their own history even if you never mention it in the story as it may help add depth to the world as well.
These are all just suggestions and I hope they all made sense haha. You don’t have to do any of this if you don’t want to. Good luck with your story!
Also this and this are both semi related and it goes along with the idea of her having issues with things