I’m not a COG author. I can’t address that side of your question. I do write, however, both for myself and others’ pleasure. At least I hope it’s pleasure.
I don’t intend to diminish your worries, but to start writing you just … write? A blank screen/sheet of paper is absolutely terrifying. Other times, the words roil around in your head that they just burst out.
My advice is to start small. If you don’t have a firm idea yet, take 2 characters and throw them into a situation (scene) and give them a conflict. Say you got an old biddy set in her ways and a, I dunno goth or something. Your characters don’t need to be opposites. It could be co-workers arguing over who failed to fill the coffee pot or a couple deciding which family to visit for the Holidays. They can even be a couple (or strangers) attracted to one another and what happens after. In my case, I thought up the biddy and the goth first. What? It’s early!
Maybe the biddy and the biddy and the goth are stuck in the same place with no one around and they eventually start to talk to fill the silence. Maybe they both want the same things. Maybe they’ll discover their problems are similar. Or maybe it’ll turn out the biddy is the granny and she’s telling her grandkid she doesn’t have much longer.
That’s just one pair. If you already have characters in mind, then use them.
I also advocate word sprints. These are most fun with other people if you’re even a little bit competitive, but you can do them against yourself and the clock. I don’t know if you’re familiar with the term, so I’ll explain. Apologies if you already know this.
Basically choose a block of time (10, 15, 20, 30 minutes are the usual time blocks) set the timer, and start writing. Don’t stop. Don’t pause to correct or rework a sentence. Just vomit it all out onto the page. Your goal is to get as many words down on paper before the buzzer sounds. You’ll be surprised how well this works. I hate writing exposition even when it’s needed. Sprints help me get through them. I’ve also discovered they work great when writing suspense–e.g., someone being hunted through an abandoned house. It doesn’t matter if you’re left with a mess that needs to be rewritten. You’re working on your rough draft. You won’t have perfection. Perfection is boring.
You can find tons of word prompt compilations online if you search if you’re short on ideas.
COGs lend themselves to outlines, especially since you have multiple outcomes. A writing outline is not like your old school literature outline. I usually start out with, “This is my character … I think. And she’s going to be this sort of person–a barrista maybe–for now. Aaaaand … hmmm, I’m not sure what’s actually going on yet, but I want her to start around here and have her wind up waaaay over there at the end because after something something something happens along the way and now she’s suddenly Queen of the Universe!”
So I’ll have a character idea (subject to change) and a vague place where I want to end up. Those are 2 bullet points. Then I sit and ponder, maybe stand up and get some coffee and ponder, call myself all sorts of names because I’m hard on myself, then put down some obstacles in the character’s path.
“To become the Queen of the Universe, Jess (that’s now her temp name) somehow gets elected to the plebe section of the Universal Congress. Someone probably thinks they can use her. Does she know? Does she care?” Then I think up another obstacle. I keep adding them until I think I have enough.
Your outline is fluid. It will change as you firm up ideas. Sometimes you’ll want to rewrite entire sections. Other times, you’ll jot down the ideas and decide to address them in the rewrites. The point is that outlines aren’t scary things. They’re a shopping/To Do list of what you want to write. Mine are really bare at the beginning.
I don’t know where you are in your writing journey. You probably know all this stuff already. Your toughest part is that first blank page. Who cares if it stinks? (It’ll probably stink. Just about everyone’s drafts stink. You’ll reread and think, ‘Ugh! How did I write this drivel?’ And then you’ll encounter a section that feels just brilliant (or at least surprisingly good) and you’ll realize you can do this after all.
So I advise you try sprints if you have problems getting the words down on paper. Put your fingers on the keyboard or grab that pencil and write. It doesn’t need to be coherent. Once you do that, you’ll realize you can do it, and the rest will be easier.
Oh, and I regularly critique my writing (in writing) as I sprint. Stuff like, “This is god awful. What are you thinking? OMG you just wrote the worst cliche. CHANGE that later!” I also use the old newspaper “TK” (for to come later) when I can’t think of the right phrase. So I’ll type something like, "Jess grabs her blaster and blasts (TK-- blaster and blasts? That’s awful. Think of a better word). I later search out all the (TK-- parts of the manuscript and edit them. Don’t spend hours and hours coming up with one word or phrase. Move on.
I have one final tip. Jot down where you plan to go next. If you have a great idea for something upcoming or a wonderful phrase, write it down before you sign off for the night. I start the day rereading the previous day’s work. I sometimes make small edits, but not huge ones. My mind is like a sieve. It helps me to have those notes at the end.
I hope some of this helps you. Writer’s block is a terrible thing, but it can be overcome. You are a terrific writer. Never doubt yourself. Writing, like any creative endeavor, gets better the more you do it. If you’ve ever taken up an instrument, learned to sew or craft, tried to draw your favorite anime character, you’ll know what I mean. So just keep writing. Before you know it, you’ll have become Queen of the Universe!