#1 First Things First Don't Panic
Forget everything I just said. As much as its all true, don't let it scare you. Yes, your opening sentence needs to be amazeballs but your first draft of your first chapter doesn't have to best seller standard. It just needs to be honest, real and original. It needs to be yours. Don't let this overwhelm you. Just give it your best and see what you can make of it. Have a glass of wine and relax. Writing is always easier when you're not on edge. Writing chapter one can seem like too big a task but you can do it.
#2 Decide on Tense and POV and Stick with it
For your average reader this may not matter too much but for those of us who do care, it matters a lot. For a reader like me the worse thing you will ever do to your book is muddle around with tense and point of view. It ruins the natural flow of your words and there is nothing worse than bad flow. Back in the day it was a bit easier. POV was either first person, third person limited or third person omniscient and without fail you'd always write in the past tense. Today that isn't the case. We mix point of views - he has a chapter, she has a chapter... that's always great. Shifting viewpoints really gives the reader a bigger scope of information but I would limit it to chapters, not paragraphs or it's just going to get messy. I like writing in the present tense and the past tense but it's important to make sure it flows so try not to mix it up. To work out what works for you try re-writing your first chapter in a couple of tenses and see which seems more natural. But if you find later in your book that your tense isn't working that's okay. You can always change it but it's going to be a tad time consuming so try to get this pegged as early on as possible.
A good hook is completely necessary. Without it you've lost your readers before you've even won them, You need to decide what your hook is going to look like right at the very start. It might come in the form of a question your readers desperately need to answer or to bring them straight into the action or show them a moment of weakness for the protagonist - whatever you choose the key is to build suspense. You need to make them feel as if they MUST keep reading right until the very end. If you know what your hook is, the thing that will keep your reader, till the very end, you will know how best to bait your hook. Your first chapter is the bait on the hook. A great way to bait your reader is with a bit of mystery. We love questions. We love leaping into the unknown. The best thing is it makes the reader wait for context. It's almost a guaranteed hook. Draw them in with a bit of mystery, keep them confused with little illuminations of understanding along the way until you are ready to hit them with context.
#4 Know what your book is about
What does your book want to say? Know your themes. As writers one of the important jobs of the first chapter is making sure the reader knows too. It's all part of that tension thing. If the reader knows what the book is about they will invest in it. In my first book, Broken Rules, it was all about Aurora finding herself. I wanted the reader to go on a journey of self discovery with her as she rebelled against everything she knew and hopefully found herself in the process. What are the stakes? What's at play? What does your character risk loosing if things go wrong? What can they gain? The other thing you need to consider is what you as the author are trying to prove... is it that love is real? or that sometimes it can be about more than just sex? or that friends can become lovers and not lose their friendship? What is your book trying to prove?
#5 Introduce Your Character
Very rarely and definitely not in the romance genre would I ever recommend not introducing your main character in your first chapter. Truth is you want your readers to love your characters just as much as you do. Who is your main character? What is he/ she doing when they are introduced? What does it say about them? What do they care about? How was their life disrupted by the plot of your story? Why should your reader care about your protagonist? Broken Rules introduces Aurora immediately. She's in a conversation with her best friend Tallulah. In the first paragraph, you can tell Aurora pays attention to detail. By the end of the first page you know she loves her friend and that she cares, like really cares. By the end of the first chapter you know how she sees her friends, how she sees herself and how she thinks everyone else sees her. "Everyone calls me perfect; the perfect daughter, the perfect student, the perfect friend, practically perfect in every way, I might as well be fricking Mary Poppins." We also know that her life as perfect as it seemingly is doesn't satisfy her. She feels stifled. But we still like her because as much as all that is true she unlike so many people before her, owned up to it and took responsibility for it. If your reader gets to the end of the first chapter and doesn't feel anything for your main character, you've failed. You've lost your reader. You don't need to tell us their life story, just enough to make us care. Why does their story matter? You could write the worst story known to man and if I care about your character I'll follow them through it.
I've said it before but this might be the most important thing in your whole book so I'm going to say it again. Tension is a must from that very first sentence to the very last. Tension doesn't always look the same. It comes with action, dialogue, emotion, sexual tension... they all work but you need to work out what's going to work best for your first chapter. In another of my books Repeating History the opening chapter is full of dialogue between my two protagonists. They hate each other but secretly are both attracted to each other. Their conversation keeps the chapter moving on with masses of tension. One way to build tension is to consider where you start your story. The later you bring your reader in the greater the tension. The first chapter might be the beginning of your book but it doesn't have to be the beginning of your characters' stories. In fact if it is you've just ruined your character. They won't be proper people - they'll be 2D ideas instead of multi faceted human beings who have lived and breathed, hoped and dreamed, cried and laughed before we even meet them.
#7 Voice
As an actor has to get into character so do you! If you are writing from your character's pov then you need to make their dialogue sound like them and their thoughts seem realistic. Immerse yourself in who they are so it becomes almost real. The author should be lost so that the characters can be found. It's important to consider gender, personality.... and everything about them when you write their voice. A guy isn't likely to get all mushy and a girl might talk about clothes or make up. Consider what you know about your character when you begin to delve into their voice. In the first chapter your character's voice needs to be strong. It needs to be confident, almost demanding.
#8 The Opening Line
Make it strong, make it assertive, make it powerful., make it memorable, make it count. A great first line is the making of a great book. Readers love a good opening line. It can be witty or emotional. It can be so many things but most importantly it needs to be short and devoid of extra crap. It's a sentence that is out for a fight and will take no prisoners. It's a promise that the rest of the book will be equally as good. It inspires the reader to read. It needs to get under the skin.
#9 The Importance of Dialogue
Make your character talk. Dialogue is key to getting to know your character. It's the fastest way to get to know each other. It's the same as when you make friends with someone new. You talk! Let your protagonist talk. Show us what matters to them. In fact even better let them tell us.
#10 Conflict Wins
Conflict is all interlaced with that tension stuff we were talking about earlier. Conflict is essential, especially in romance. It means that your character has to do something. Drama creates conflict. Start with conflict. We all know that people love gossip and drama, readers are no different. Conflict changes everything. It might be big or small but it impacts the character and the reader alike.
Don't let it drag on. You don't need to tell your reader everything in the very first chapter. It's not only not necessary, it would be a waste of time and a mistake. Your reader won't hear it all and perhaps more importantly they'll get bored. And that's the kiss of death to any book.