Who is the narrator, can she or he read minds, and, more importantly, can we trust her or him?
Third Person, First Person (Central)
Don't be fooled by the way the book starts out in third person; Nina, our narrator, soon switches to first person to tell her story. In Chapter 1, we see a move from this kind of sentence: "Nina had already donned her sunglasses, which were big, heavy, wraparound things that made her pinched face look smaller than ever" (1.30), to this kind: "The plain fact is, I can't do anything much. That's part of the problem. Vampires are meant to be so glamorous and powerful, but I'm here to inform you that being a vampire is nothing like that" (1.32). Hello, Nina.
One of the side effects of us hearing about Nina's life from her as our first-person narrator is that we're constantly in her head. So, like in the above passage, we get to know what she thinks and feels. We get to hear (over and over again) how much she hates being a vampire, and we get to hear about the gross stuff she has to go through, like feeding on live guinea pigs.
There's one exception to all this: In two chapters (16 and 25), Nina tells us that she's going to cheat and talk about stuff that happened while she was knocked out during the daytime. Then she switches to third-person to talk about those events. We gather that she pieces this stuff together later after talking to others, since we find out at the end that this whole manuscript is presumably her memoir.