Design the world in which your vampires will live and the laws that govern their world. Are your vampires operating under the traditional rules of the vampire? Do your vampires have the same weaknesses as traditional vampires? Think about being unique. Maybe sunlight isn't as deadly to all of the vampires in your novel. Why not?
Create unique vampire characters. Every vampire doesn't have to be dark, mysterious and dripping with erotic sexuality. You can have those vampires in your novel too, but think about creating vampires with the traits and personalities of everyday people.
Respect vampire novel traditions while striving to be unique. Changing the rules of the vampire novel is okay so long as you respect the inherent traditions of the genre. Readers of vampire fiction expect certain elements of their vampire fiction to remain intact, so your goal as a writer is to find a unique, fresh approach to telling an age-old story.
Remember to create a variety of characters. Not all vampires are bad. Some operate in shades of gray. Others may be good. Think like a vampire when you're writing your vampire novel and you'll create prose that's more believable.
Writing dark and Gothic is okay to an extent, but try and put your vampires in modern, normal settings as well. They don't have to live in creepy castles and sleep in coffins. Those are the sort of cliches you want to avoid.