Incorporate scientific plausibility
Writing a science fiction is writing a fantasy but while you write a fantasy you should keep it in your mind that the fantasy should be related to the reality as well. Before writing a science fiction you should get a proper knowledge of the world you are creating. For that you can read a book or watch a movie related to the story line you are making.
Create and then conflict
No stories complete without creating a conflict within the harmony because if the story only goes in one direction then it will become boring. There are multiple ways of creating a conflict such as:
1) first of all decide what your characters like or love.
2) give them something to fight for.
3) create small and big obstacles throughout the plot.
4) put the antagonist and protagonist in a love hate relationship.
