A good opener sets the tone. It sounds trite but capturing that opening tone within the space of a single line can be an exceptional challenge. It is very easy to drive yourself cleanly into Bulwer-Lytton territory ("It was a dark and stormy night.") without even noticing. I've done it several times and once it has been pointed out by the outside observer, it is often shockingly, glaringly obvious that you are now deep in the weeds.
So what makes a good opening? The answers are as varied as there are openers however one thing tends to predominate - having an opening line with an intriguing, evocative or substantive hook. The hook is what draws you in, drive the reader's attention and ideally pulls them into the next sentence...and the next one and so on.
"The sky above the port was the color of television, tuned to a dead channel." —William Gibson, Neuromancer
Gibson is an exceptional writer and in the space of a single sentence he manages to evoke a multitude of the key elements that inhabit his story - technology, a modernized bleak sense of emptiness, and a brush of the familiar, a future (television) that all readers can readily associate to and understand.
There is one school of thought that lays claim, as per the Bulwer-Lytton example, that providing a descriptive sentence as an opener is not a good approach, that it falls under that "purple prose' category but I disagree. I suspect a strong descriptive passage can and does work as an opener, if used effectively. One example is Richard Adam's classic Watership Down.
"The primroses were over."
The sentence aptly presages the changing world that the characters face.
In developing The Jesuit Letter, I went through several variations of the opener. Prior to adding the prologue as an opening chapter the opening was:
"The nudge in the ribs was short of a kick, but not by much"
This was a straightforward intro into the character and his situation, with the sentence meant to spark an interest as to the question of just why it was so close to being a kick, who was being almost kicked and why.
After adding in a Prologue to further the storyline, the opening was changed to:
"The April dawn was grey, damp and muddy and tinged with the mixed smell of early spring and winter’s rot. "
This was a nice descriptive sentence and keyed up two of the themes around growth and death but it failed to have a particularly strong hook and, shades of Bulwer Lytton, focused on the description rather then a hook. After receiving some feedback from a helpful agent, I re-visited it and it was re-written.
"He hoped it had been a clean death."
This provides a much stronger and more interesting hook and pulls the reader into wanting to determine why, who and how.
Whether it stays or is re-worked again, only time can tell.
The American Book Review has a list posted of the top 100 opening lines starting with "Call me Ishmael.." from Moby Dick and ending with The Red Badge of Courage. I can't claim to an acquaintenance with many of the books on the list and whether you agree with the list or not is entirely subjective, but there are some great opening lines included.
Here's a few openers (aside from the Gibson quote above which is also on the top 100 list) that have caught my eye over the years:
"He was born with a gift of laughter and a sense that the world was mad." - Raphael Sabatini, Scaramouche
“No one would have believed, in the last years of the nineteenth century, that this world was being watched keenly and closely by intelligences greater than man’s and yet as mortal as his own; that as men busied themselves about their various concerns they were being scrutinized and studied, perhaps almost as narrowly as a man with a microscope might scrutinize the transient creatures that swarm and multiply in a drop of water.” - H. G. Wells, War of the Worlds
"Many years later, as he faced the firing squad, Colonel Aureliano Buendía was to remember that distant afternoon when his father took him to discover ice." —Gabriel García Márquez, One Hundred Years of Solitude
“Midway in our life’s journey, I went astray from the straight road and woke to find myself alone in a dark wood.” - Dante, The Inferno
"In a hole in the ground there lived a hobbit." - JRR Tolkien, The Hobbit
"Women, how they do haunt this tale." - Bernard Cornwell, Excaliber
Feel free to drop in any of your thoughts, or your own favorite opening lines in the comments below.