On writing

In an earlier comment, Hristo Naydenov asked:

I don't wanna be a nuisance, but as someone who wants to write sci-fi, I find it quite difficult to figure out how to start. Maybe the foundation doesn't have to be a truly original concept, but the development that follows has to be. Where did you get your inspiration from? How do you start writing something so amazing? Do you start off based on a single, simple idea, and build as you go, or do you have a big outline that depicts everything that you ...