(Raymond Chandler, The Big Sleep)
Whatever I've been writing, I find that the opening needs to be written last. That might sound a bit contrary but believe me it works much better this way.
I have a tendency, in common with many writers, to start a story with some stuff that is best described as 'backstory'. Information that's necessary for the writer but not needed by the reader. Things like what the protagonist looks like, what he had for breakfast and the number of the bus he gets to work.
These days, I try to write the whole story from beginning to end and then decide what's needed and what isn't. Then I have a go at the opening few sentences to see if they're the right ones for the story.
Openings are of crucial importance. They set the style and tone for the whole piece. They also, crucially, invite the reader to read on. The best openings include enough information on character, setting and plot to engage readers without giving them indigestion.
My favourite opening paragraph is reproduced above. I love everything Chandler wrote but the beginning of The Big Sleep is quintessential Chandler. Here we meet Marlowe, perhaps for the first time. We learn a huge amount about this man from the way he describes himself. Neat, clean, shaved and sober might seem unremarkable but the fact that he takes the trouble to mention it indicates that these are not part of his default state. The details of what he's wearing down to the pattern on his socks shows he's been very methodical in deciding exactly what to wear. And that the meeting is very important. And that Sternwood is very, very rich. And so on. All shown to us in an effortless way that lets us form our own opinion of the protagonist. Awesome. I love it.
Oh, and the second paragraph is just as good. And the third...
If you haven't read The Big Sleep then I suggest you do. If you have read it, read it again and this time remember to marvel at Chandler's technique as well as enjoying the story.