Well, you avoid most of the typical tropes or put your own spin on them. In a lot of stories, the big thing about vampires is that they are both more and less than human; they are set apart from normal humanity by their immortality, superpowers, addiction to blood, and inability to bear the sun. The authors usually take the perspective that these things are unnatural and should be destroyed.

In UF, there are so many badass immortals among the good guys (Detians, gods, robots, other long-lived races, and people who've just found a way to avoid Father Time) that there's no need to play the "Woe is me, I have a skin condition and specific dietary requirements" cards. You take these vampires out of their original context, and put them in a universe and social circle where what species they are matters far less than what they do with what they've been given. For instance, Roger Tremayne and Devlin Carter are both P12 psions, with almost identical basic powers, but one is a tyrant and the other is a liberator.

Back on track, I figure that you like the aesthetics of vampires, especially cute vampire girls, and pick ones whose personality idiosyncrasies mesh well with those of the other characters in the story. I'd be throwing quite a few stones in this glass house if I said there was anything wrong with pulling characters out of context just because you think they're cute or hot.