Hey guys, first time writer here..I know this is a personal question, but how do you guys plot out your story? And then decide on the pace? I've been trying to write forever and I can always write starts and middles but I can never seem to complete a story or decide on how to significantly move the plot.
Having your ending down before you start is a good idea - even if you don't know the exact way to get there, you'll at least have a goal in mind when you're writing. I've always known how each of my stories ends before I get far into writing them.
Otherwise there are two schools of writing plot: making it up as you go along and outlining it all in advance. I've had success with both, but if you're struggling with pacing I'd suggest writing a short chapter-by-chapter outline - give each chapter a few short sentences to describe what needs to happen in it, and have every chapter either move the plot forward or introduce a significant obstacle of some kind. This isn't a hard-and-fast rule but it's a good starting point.
Also try to give all of your major characters goals or personal wants of their own. If you're short on ideas at any point you can then fall back on those.
I would add to this that you shouldn't forget that finishing a book is just the first of many steps of actually completing a book.
worrying about pacing is a good thing, but there isn't a reason to be bogged down with worry. Your first draft... it's likely going to suck. Most do. It's fine. Pacing is something I tend to worry about more in editing as it's far easier to see where things are actually dragging or are moving to quickly when I step away and come back and look at it again. (at least it is for me)
As Xagarath said having an ending in mind helps quite a bit. Not even talking about an in depth ending. Even a single sentence of how you want things to end can be fine, you just need some sort of plan to work towards.
As for how I plot my story, I'm far more of a pantser (making it up as I go along) but I do some outlining as well. I've found for pantsing it's very helpful to have well defined characters. Get in their heads, figure out how they would react to a lot of things, and they will kind of guide you to where you want to go (or absolutely go against what you have planned and when you think about it they wouldn't do what they want you to do so you have to scrap your plans and figure out something new >.>)
I have general beats for my story. Motivations of the heros and bad guys, what conflict is going on, how it's going to be resolved, but nothing to much in detail. Every time I try doing detailed planning one of my characters ends up forcing me to throw most of it away lol.
My big thing is I try to write every day, so what I do is I spend my free moments at work, or while playing games ect planning out the current scene in my story. Constantly running it through my head to find a flow that I like. I've literally spent 4 hours at work planning out 50 words before running the exchange of two characters in my head hundreds of times as I tried to decide how I wanted to go with a scene.
Also, don't forget that while writing can be fun, it won't always be fun and you have to be willing to write even when you don't really feel like it. The odds that you will enjoy every step of writing something are almost zero. Just keep at it even if you think what you are writing sucks. There's almost always potential to make a garbage story good in later drafts and editing, but you can't do later drafts and editing if you don't write the story to start with.