I may never be asked by budding writers how to do it, but if I am then I know what to say. It's not original, and if anyone has some other thoughts on the subject, run them past me! But I'd say, think of something that you would really hate to see happening, and write a story about how it was prevented - the lead characters being the ones who do so. Or else write about something you would love to see happening, and design your plot around how the central characters make it happen. Of course, the characters have issues to resolve also. But when you do that, it can be a great relief to think of a good outcome, even if it is fiction. I wrote the first novel I ever did about a group of high school age kids, and the way in which the youngest one is often left out of things; and the action resolved when the others in the gang see the need to include the younger one. It was thin, hardly a profound plot at all, but that is what makes me want to speak my mind and lay out a better way. Christianity provides the spiritual input because, the longer I live, the more I can see how it is a 'try-hard' thing to try and make good outcomes in only human strength, and with only secular philosophy. The world is full of people who would like to see things get better. But huge effort has been made, and little has come of it, because the instigators left God out of the equation. Sometimes the results become quite monstrous. Communism was supposedly a doctrine to make a caring, greed-free and strife-free world society; but it relied on human strength and direction, and degenerated into brutish and vile dictatorship. It tried to set up some Christian principles but denied the Christ His place in the scheme of things, and led to a shocking fiasco.
One of my favourite books in Frank Peretti's "The Oath". It shows, graphically, how human sin grows and gets more control. And even people who start off with good intentions, without God, will eventually be duped by their own folly into fouling up the thing they try to created. If only more people could see that! But some would accuse me of ramming my ideas at them simply for saying this! Still, in God, all good things can come to pass.