Read more books. At first, you can read some books that teach you to write, and then read some novels, stories, masterpieces and so on. Trying to figure out the plot and details. The climax, the author's conception, etc. Then I began to write with a pen. It doesn't matter if you can't write it at first. Take your time, practice every day or occasionally, and eventually everything will pay off over time.
In fact, the improvement of writing ability is still not the ability to conceive a good story, so you need to read more books, observe life more, and then keep it in mind, so that you can write a good story when you start writing. Stories are the most important thing than good writing. After all, writing can be practiced slowly, but stories cannot be practiced slowly. Need inspiration.