Any story has 5 sections:

1.Introduction - (Where the reader/player knows where he is in time&space)
2.Intrigue - (The cause of the story)
3.The action - (what comes out of the intrigue)
4.The action peak - (The most tensed point of the action)
5.The conclusion - (What have we learned from this, what was the point of everything)

When building a story I recommend imagining it from point 5 to point 1:
First step : What do I want to say with the story?
Second step: what happenings can get me to my point logically and relevantly?
Third step: What can cause those things to happen?
Fourth step: Where and when could this happen?

ADVICE: don't aspect to write good game stories for games by playing games, read books, both classic and modern, books help you expand your imagination and teach you narration techniques.

I am a programmer and software consultant as a job, though I've read more than a 100 books in my life, including some philosophy (good for conclusions), psychology (good for building relevant characters), hundreds of stories (from Asia, Eastern and Western Europe) these help you with plots and places. I write stories from time to time (when I have it), I don't publish because I don't have the time to invest, but I've submitted my work to book editors and they appreciated them, as well as some of my friends deed.