"I want to write a book, but I don't know how to get started."
That's something I hear quite often. Everyone's style of writing is different. If you put a dozen writers in a room with pencil and paper, you will come up with a dozen different writing styles.
There has been much written about the differences between male and female authors. One person thinks males want to save a country, whereas females want to save a relationship. I definitely fall into the latter category. I think there's something magical about those few precious, golden moments when a man and a woman first meet. I'm a sucker for a good love story as well as a sprinkling of "blood-and-guts."
First, you have to have an idea--the seed of a plot or character in a situation.
The first thing is to write the "dreaded" synopsis. I don't know why some writers are so consumed with fear concerning the synopsis. Maybe changing the name to "Outline" would help. I want to get my idea on paper as quickly as possible. At my age, I've gotten a little forgetful. I even keep paper and pencil beside my bed, beside the sofa when I'm watching TV and in my handbag when I'm out-and-about. You never know when that fantastic plot twist will strike.
Write the basics of your story as if you were explaining it to your best buddy. You shouldn't care about grammar or punctuation. Just get it down on paper. Of course, it isn't written in stone. It's your story, you can change it as the plot unfolds. You really need this guideline to keep you from wandering.
Next, make up a "cast of characters" in line with your new idea. To me, this is the fun part--creating new people. Pick a name, age, physical description, family back ground--parents and siblings, marital history, education, job history, pets, even the make of car they drive. Even if none of this is mentioned in your story, you need the info.
How a person reacts in any given situation is usually based on past experience. Are they stable or will they fall to pieces? How will your characters react in a sexual situation or in the face of mortal danger? Believe me, it matters.