I can't remember what show I was watching or which book I was reading, but one character needed to tell another what had happened. She says, "I don't know where to begin."
He responds, "Begin at the beginning."
For novel openings, this is bad advice. Hall likens this to starting to cook after your dinner guests have arrived. The beginning of nearly anything is boring and won't catch your reader's interest. The other common advice is begin with action. Although this is slightly better than begin at the beginning, I don't find it fantastic advice either. For one thing, action can be confusing when none of the characters or even the setting have been introduced. (And confusing the reader is the greatest sin of an opening. Nothing stops a reader reading more quickly than confusion.) Second, if the reader doesn't care about the characters, the action has little to no emotional impact.
An effective opening needs to do three things:
1) Set time and place.
Readers need to be oriented to the world they are inhabiting right away. Not in intricate detail, but enough so they feel grounded. The reader needs to know if she is in contemporary USA, medieval Europe, or a space colony orbiting the planet Xenon. Let's look at the opening of Storm Front, the first book in Jim Butcher's Dresden Files series:
The mailman walked towards my office door, half an hour earlier than usual. He didn’t sound right. His footsteps fell more heavily, jauntily, and he whistled. A new guy. He whistled his way to my office door and then fell silent for a moment. Then he laughed.
Then he knocked.
I winced. My mail comes through the mail slot unless it’s registered. I get a really limited selection of registered mail, and it’s never good news. I got up out of my office chair and opened the door.
The new mailman looked like a basketball with arms and legs and a sunburned, balding head, and he stood chuckling and reading the sign on the door glass. He glanced at me and hooked a thumb towards the office glass. “You’re kidding, right?”
I read the sign (people change it occasionally), and shook my head. “No, I’m serious. Can I have my mail, please.”
“So, uh. Like parties, shows, stuff like that?” He looked past me, as though he expected to see a white tiger, or possibly some skimpily clad assistants prancing around my one-room office.
I sighed, not in the mood to get mocked again, and reached for the mail he held in his hand. “No, not like that. I don’t do parties.”
He held on to it, his head tilted curiously. “So what? Some kinda fortuneteller? Cards and crystal balls and things?”
“No,” I told him. “I’m not a psychic.” I tugged at the mail.
He held onto it. “What are you, then?”
“What’s the sign on the door say?”
“It says ‘Harry Dresden. Wizard.'”
“That’s me,” I confirmed.
“An actual wizard?” he asked, grinning, as though I should let him in on the joke. “Spells and potions? Demons and incantations? Subtle and quick to anger?”
“Not so subtle.” I jerked the mail out of his hand, and looked pointedly at his clipboard. “Can I sign for my mail please.”
The new mailman’s grin vanished, replaced with a scowl. He passed over the clipboard to let me sign for the mail (another late notice from my landlord), and said, “You’re a nut. That’s what you are.” He took his clipboard back and said, “You have a nice day, sir.”
There is no long description of setting here. But the reader is oriented. We have a mailman delivering mail in an office building. This clues the reader in that he is in contemporary America. Also, that we are probably in a city. We also get the idea that this is urban fantasy because Harry insists that he is "an actual wizard." The reader can feel comfortable; more details of setting can follow later.
2) Make the reader care about your main character.
If the reader doesn't care about the character, she rarely cares about the plot. If we don't care about a person, why would we care what happens to them? Butcher makes us care about Harry in his opening. He is about to get bad news. We can sympathize with someone getting bad news. He is used to mocked. We tend to side with people being made fun of. Yet he has an attitude. The sign on his door announces him as a wizard even though he knows he'll be laughed at for it, and in the midst of being mocked, he doesn't take the easy out the mailman gives him about doing children's parties. We like that kind of strength.
3) Intrigue the reader.
You want to present the reader with a mystery, make them curious so that they need to read on to learn the answer. What is this bad news that Harry just got? Few readers would stop before learning that. What does a wizard do in a world where people think he's a nut?
This beginning is certainly not at the beginning of Harry's story, which we will learn later through flashback. Nor is there a lot of action. A mailman knocks, Harry answers and gets his mail. But if the reader is anything like me, she will certainly go on reading, for the next fifteen books. When, oh when, will #16 be here?
While the beginning of a novel is absolutely crucial to selling your book to publishers, agents, or directly to readers, as a writer, don't worry about this when starting to write the novel. It's nearly impossible to write a compelling beginning or to even know where the story should start if you haven't written the novel yet. A compelling beginning is created in the revision process, not the first draft. So don't spend so much time agonizing over your opening so that you never actually write the novel. Start wherever you feel inspired, and fix it on revision.