Starting to write my book

I've been contemplating writing a novel for a long time, and I've actually started to write it. How do I start?

My book is based on an ongoing dream. Thanks to Charlaine Harris and her books, I got the idea in my head and haven't been able to let it go. For now the title is "Angel and The Vampire." Building the characters is always the challenge and the decision of how to describe them. How old to make them. What names to give them. The scenes in my head after a night's sleep are always somewhat changeable. Can I describe them so others can visualize them too? I hope so. Deciding where the scene should be and how believable it should be, is another of those things one has to decide.

When I took writing classes years ago, it was always recommended to choose places you are familiar with in order to make a description believable. I've gone through many places in my mind, since I've lived in or visited many. The primary considerations being Houston or Corpus Christi, Texas; Denver, Colorado; a small town in northern Kansas; North Miami, Florida; Seattle, Washington; Missoula, Montana; Farmington, New Mexico; Bloomfield, New Mexico. Or should I rely on memories of my childhood home in Ohio. Looking at past vampire books, most are set in Louisiana.

Vampires have been represented as dead people who have been reanimated to life in the movies. They have been shown as having no reflection, allergic to garlic and sunshine. That is until the Twilight books. In them, vampires are shown as immortal beings who died and arose from death in a form that doesn't require sleep and can exist in the daylight as long as it isn't bright sunlight. From that book series, vampires don't burn to death in sunlight. In all interpretations of vampires to date, they are romantic characters who exist only on blood with a vicious even homicidal streak in order to fulfill their need for blood. I think I will change that idea in my book. Part of the lure of my book will lie in how my vampire character is different from the others and living among us today along with other supernatural characters.

How does an Angel play in the book? Well, that is an interesting twist to the story and actually, she is the main character. She won't even be aware she is one for part of the book, and will find out her true nature and power due to the vampire invading her life. Does this mean this will be the only book? Will this lead to a series of books? Will the book be entirely serious or like Charlaine Harris, have a touch of comedy to it? Or will it be totally romantic while taking advantage of the horrific nature of a vampire? As the book develops, more will be revealed.