The soundtrack of words is so personal at first, I just keep it in my head for a while, letting a few impressions form. A character shows up first, with a story to tell, but it's not in focus yet. I'll take it to bed with me, to my island, or break time at work. What does this character want to say? If she's a guest at the island, and if she's ready, she will come in as clear as a song. That song is her life, her opinions, and actions. All I need to do is start writing. I love it when that happens. Then more characters show up and I start seeing a plot. Before I know it, I've got that new story or novel.
I prefer to write the fantastic stuff, and the best way to write about that alien or vampire is to provide as much detail as possible. Description, lots of it, is the key. A vampire can always be seductive or beautiful, but what else? You can make new rules or stick to the old. Maybe that vampire can walk around in the daylight or drink wine. The writer will have some explaining to do, but that's where inspiration can be found. But don't underestimate the reader. If your reader is a big vampire fan, don't bore them. This person may have read tons of vampire fiction, along with movies and TV shows. This is where description comes in, along with all of your imagination and skill. Give that vampire fan a thrill, everything they want with something new thrown in. Because you are not just the writer, you are the reader, the very first reader, of your new work. Objectivity is almost impossible at first; I have to put the completed draft aside for almost two months before I can see it with a more critical eye. Put it aside for a year, if you can. I know I can't, but I respect that kind of self-control.
I'm still on the island, my guest is coming closer. When I see his face, I start to hear the story in his eyes. Telepathy. The best stories are told this way. :)