I'm writing a book with vampires and I want a mix of all the cool stories of jow they came to be.
The standard origin is Dracula, the first known vampire, he is the son of the devil. But feel free to be creative, they don't all need to have Dracula in them. Don't do anything too stupid with your vampires either, by that I mean don't go to the people who made the Twilight movies for inspiration. You also don't always need an origin story, you can save that for a sequel or trilogy. Turning into a bat is a little cartoonish and out of style, just give your vampire the ability to fly and super strength, the ability to heal like wolverine and of course the drinking of human and occasionally animal blood, and try to avoid the amnesia thing. People get annoyed with that because amnesia is used too much. You also want to decide if you're going to focus on an action/vampire movie or a drama/mystery/suspense type movie, don't be afraid to put a little erotica in your film, just don't be graphic with the love making part.
I've been a fan of the vampire genre since I was young, but it's surprisingly difficult to find a vampire movie that is truly good and original. The last movie I actually liked was Van Helsing, despite the amnesia part of the movie it was still good. If you haven't yet, I recommend reading a lot of vampire novels, good ones and bad ones, and watch vampire movies to get more knowledge and a feel for the genre. You should also study the actual history of the name Dracula, the more you know about the genre and the stories out there, the better. You may be surprised with how little you know about the genre which may be why you're having a hard time with your origin story.
I hope this at least helps you some.
The Vampire Origin Story
Ambrogio was a young adventurer. Born and raised in Italy, he had always longed to travel to Greece to have his fortune told by the Oracle of Delphi. When he was an adult, he got on a boat and sailed to the western edge of Greece, near Astakos. He traveled east until he eventually reached the city of Delphi.
Delphi was home to a great temple of Apollo the sun god. It was also the home of the Pythia, better known as the Oracles. The Pythia would sit in a chamber within the temple and speak of prophecies, inspired by Apollo, to those who came to seek the Oracle's wisdom.
When Ambrogio finally arrived at the temple, he went to speak to the Pythia. The Pythia, whose words were often cryptic, said only a few words: "The curse. The moon. The blood will run."
He couldn't sleep that night. He stayed awake outside of the temple, pondering the meaning of the Pythia's words. As the sun rose in the morning he realized that he had not slept. As he walked back toward the town he saw a beautiful woman dressed in white robes walking to the temple. He ran over to her and introduced himself.
Her name was Selene, and she was a maiden of the temple. Her sister was the Oracle, and so Selene tended to the temple and took care of her sister while in her entranced state.
For the next few days every morning Ambrogio met Selene at dawn before she entered the temple. They soon fell in love.