I'm going to be honest with you here. I discovered very early on when I decided I want to write novels that the absolute worst thing for me to do was to read about writing or listen to advice about writing. Partly, because I am contrary and don't like being told what to do. Partly because I really want to know how to do these things and generally think everyone knows more than I do and maybe listen too much.
Yes, I know those two thoughts don't seem like they should belong in the same space in my mind but they do. Contrary, as I said. Anyway, I found, when I listened to someone else tell me how to do things and I tried to it I just ended up stuck. So I hid in a closet and just wrote a lot. This is a fine method if you are A) Stubborn and a bit foolish and B) Happy that it might take ages to get anywhere.
Anyway, that's my disclaimer, just because I do a thing doesn't mean that you should, but maybe I'll say something useful that you can cherry pick. Who knows, first time for everything and all that.
I never really think about pacing when I write. I just write a book. However, I can retcon with the best of them so lets get on with how I think I do things in hindsight. For this, let's make use of bullet points, like I am professional.
• It's a lot easier to have a pacey book if a lot of things are happening.
• Pace comes from plot. Plot comes from character.
• If you know the end and a few things you want to happen along the way you can use these as milestones to work towards.
• A three act structure is a wondrous thing.
• Keep asking yourself, 'do I really need to say this?'
• Ending each chapter on a minor cliffhanger is a really cheap trick. Use it mercilessly.
I like to think of a book as a succession of increasingly high waves. In fact, a lot of writing for me I see as shapes so there's probably a touch of synaesthesia about it. Some of this won't help most people much but the idea of waves, I think, is a good one. Build to a point where things happen, then have a lull, let people recover and build again, but this time to something a little more dramatic, another lull. You can keep this going throughout the book, gradually raising the stakes.
Or you can see a book as three (or five, or seven) big waves – but that pulling back is important. It's a bit like a resetting of the reader. Chapter Four of Age of Assassins begins with two pages of description. It's not even, strictly speaking, within the narrative. Girton isn't in a place he can see what you are being told, and probably wouldn't know it. It's an intrusion, an omniscient narrator coming through in a decidedly non-omniscient voice. It's very deliberate in that I wanted to quiet everything down. It comes after the set up of the book, we've had a bit of action, introduction of the main characters and an explanation of why Girton and his master, Merela, are there.
So we stop.
We've met the people, this is the place. In a way it's like starting the story again, which brings me to the three act structure. It's a really familiar thing to me from scripts rather than fiction, but it's such a very useful thing to have in the back of your mind. You introduce your main characters and what they are going to do in part one. In part two you introduce any secondary characters and create the set up for the final events. Then in part three you wrap it all up. And you can do this by creating those lulls, I do in Age of Assassins, though to tell you how I do the second one would ruin the book for you, so you'll just have to trust me on that.
An important thing, and a hard thing to keep in mind, especially in Fantasy and Science Fiction, is that you need to tell us less. There's a huge deal made of world-building, and that's not a bad thing (see also – research.) A well thought out or researched world can add a lot to a story. But it is very much a double edged sword, because if you create a huge world and get really excited about it, the temptation then is to tell the reader all about it. So keep asking yourself the question, 'does the reader really need to know this at this point in the story?' And if they really do need to know something then here's two more useful questions: 1) can I say it in dialogue? 2) can I say it in less words? Short stories are a really good thing to play with because brevity and clarity are always going to be your friends.
Lastly, and this is a really, really important thing – You know how to do this. You read. If you want to write you've probably read loads and loads so the knowledge is in you, it's just a matter of unlocking it. Hopefully, something in this will help you, but if not, don't worry, there are plenty more articles about writing out there. In the end, only you know what works for you, try everything, bin what doesn't work. Enjoy doing it.
Sentences should always feel round and never feel oblong. See, not helpful.
 I cheated a bit in this but let's not talk about that.
 I would dearly love to write historical fiction at some point BUT I know that research is black hole for me that means I will just spend all my time reading all the fascinating historical stuff and never writing anything.
RJ Barker lives in Leeds with his wife, son and a collection of questionable taxidermy, odd art, scary music and more books than they have room for. He grew up reading whatever he could get his hands on, and has always been 'that one with the book in his pocket.' Having played in a rock band before deciding he was a rubbish musician RJ returned to his first love, fiction, to find he is rather better at that. As well as his debut epic fantasy novel, Age of Assassins, RJ has written short stories and historical scripts which have been performed across the country. He has the sort of flowing locks any cavalier would be proud of.