Create a catching idea and theme for your story

Come up with the central idea of the story and the main conflict.
Write down the main problem your protagonist will deal with in the story. Everything that happens in the story should somehow be connected to your central idea.

Set the theme of your story.
Decide the general theme and message you want to deliver—for example, love, family connection, overcoming fear or some flaw, etc. Shape your story according to that theme.

Take the protagonist out of their comfort zone.
Come up with a strong wish that the protagonist has, and then place them in uncomfortable situations that will make it as difficult as possible for them to fulfill their desire.

Give the protagonist a strong motive to fight for his wishes.
Something has to hit him emotionally, so he feels a strong need to fight and overcome all obstacles.

Lead the protagonist to victory.
Think about how the protagonist will overcome the obstacles and how he will change positively during his struggle.

Plan surprises
Find out what the audience would expect in your story, then try to subvert those expectations and create a twist.