It’s said among savvy published writers that newbies have a tendency to start about two chapters in. In other words, they write an unnecessary prologue, first chapter, maybe even second chapter, and then the action of the story begins. So go ahead and write it anyway, I’ve heard at conventions, and then take off the prologue and the first chapter and that’s probably where your story actually starts.

The best advice I’ve heard, long ago, was ‘Start where everything changes.’ When your viewpoint character’s life takes a different path, when the Thing happens that affects the world and drives the character out of his/her ordinary life.

I like this advice. It’s tricky–it forces you to introduce your carefully crafted world to the reader as you go along, which can be more difficult than showing some ordinary life first, to show the rules. But it can be done, and it seems to me that it’s likely to keep the reader more interested!