A Picture Is Worth A Thousand Words
One method of painting a believable scene is to story board it. IE literally drawing out what happens. You see this a lot in the creation of movies and videogames (especially for set pieces) and they’re not just doing it because it looks pretty- they’re doing it to see if things follow a logical progression and flow naturally from one action to the next.
Neil Gaiman has gone on record stating that he sometimes writes an actual comic for scenes (or entire books) to help grasp a better understanding of where things are heading. Now, look, I’m not saying you need to be like Neil Gaiman. He is after all, a madman (and I love him for it). But if you encounter that fabled specter of “writers block” then this can help immensely.
I actually used this storyboard or “comic method” while writing my book. In what now seems a blatantly obvious choice, my protagonist was on the top of a wall (technically anyway) and needed to get to the top of a tower. For the life of me I had no idea how he was going to do it. I would start writing my outline and things would just seem off, like the actions and progression of the character through the chapter didn’t make logical sense. Try though I might it was always painfully obvious that the protagonist was doing certain things because I, the author, needed them to, and not because it was natural to the story.
It vexed me (and forced me to mutter more than one four letter word) but eventually I had enough. I took out a notebook and drew the wall and wrote a giant “A “in red ink and then the tower with a giant red “B” on top. Then, in pencil, I drew a tiny stick figure directly below “A” on the wall, along with all the various enemies, crates, and other obstacles that was in my characters way. With that done it was only a matter of playing “scenery chess” whereby one enemy moving toward the character would make them naturally move THIS way which would make it so they had to surmount THIS obstacle which meant they would have to do THIS.
In probably 5-10 minutes (and a quite frankly absurd amount arrows and notes in the margins) I had figured out how my character got to where they needed to be while making it seem like their own, natural choice (while still conforming to my grand design). A problem that had been the literary equivalent of stubbing my toe for days had been resolved in minutes—all because I drew some rough figures on paper.
Maybe you think you aren’t that good an artist (or maybe you just think you can’t draw for shit). Guess what? Unless you’re writing a comic then no one is going to see you’re beautiful disaster of a storyboard. The actual stick figure drawing of mine isn’t going to be present in my final draft, but the fruits of its labor will (I hope). The same will be true for you so don’t despair.
What you do may be sloppy, messy even, but you have no reason to be ashamed of it. It’s for your own personal use. Embrace it.
Just be sure to wash your hands when you’re done.