Hello! Welcome back :)
So, if you already chose your theme, you are a step forward on this path. Today we will have a little more ... technical. "Oh, no ... what are you saying, Ana?" You do not have to worry at all ... It's simple:
You will take your theme and choose something called PREMISE. It is the meaning of your story. I'll give you an example: if your topic is "A love story that involves a terminally ill person" (in many cases!), Your premise could be "There is nothing you can not do for love". It's simple!
Okay ... are you ready?
Write your subject, your premise and keep moving forward. Do you remember that I said that we would become a little more technical? It's because here I'll give you one of the keys if you want to sell your story. As I said in the previous post, it does not matter what you write, but this advice will help you especially if you are creating a novel or a script that you can sell to publish or film it.
You have to create something called IDEA. It is the last summary of your story. Imagine this: you get into an elevator and when the doors close, you hear a "Hello!". You stop the doors and a blazing Wes Anderson enters the elevator with you. There is no one else and the doors close. He goes to the tenth floor. You already have your script and he is a famous director who could give life to your movie ... What would you do? You only have 10 floors to convince him.
EASY! You will tell him about your idea. Do not start talking about your whole story, come back and move forward ... The idea is a summary that explains your script in two sentences. It's not easy, but I'll give you a shortcut.
You can use this formula to create your story:
Main character (s) + Objective + Antagonist + Limit
Let's create an idea:
An astronaut wants to save Mars from an evil scientist before destroy it .
It's basic and quick. One sentence (wrote in present tense) that tells everything Wes Anderson needs to know about your story to decide if he likes it or not :)
You can add some others details as the detonator of the action or something relevant that makes unique your story. Look at this:
While repairing a satellite outside their ship, two astronauts suffer a serious accident and stay floating in space. The will try to find a solution to return to Earth.
I just wrote the summarized idea from Gravity (2013).
Give it a try and comment if you have some doubts. I'll be happy to help you!