This is a story checklist of everything to keep in mind.
Get some Writing Software.
You'll have to have an idea for a story.
Some writers like to outline their story and characters. To do this, you'll want some Mind Mapping Software.
If there's any research to be done. Do it.
When thinking "What could happen next?", remember that your characters should be driving the plot. The plot shouldn't be funneling your characters down an avenue they don't fit or decide upon—the less coincidental events, the better. If the reader is to respect your protagonist, they must be active, not passive, by having goals.
Plant things early on that will return later.
Try to avoid coincidence. Again, see active protagonists.
The audience need time to relax every so often, so don't forget to give your character breathing space to reflect.
Start with a good first line.
When writing dialogue, try to have subtext. Show, don't tell.
Be self-critical, but not self-doubting. Reading a few paragraphs from a bad book that sold well can inspire.