You will notice that there is nothing groundbreaking here. There are even a couple of things that your English teacher told you to do.
And that's the point.
This is not difficult in and of itself.
You can take a giant leap in the readability of your action lines just by paying more attention to them.
It's about making a commitment to care about the little things.
You can start with these:
Visually orient us as soon as possible. Readers often skip the scene heading and go straight to the first action.
It's hard to blame them; "EXT." and "INT." are ugly, disruptive, and clumsy to read. I use them as little as possible now.
This puts even more weight on the first action line in a scene. The longer you wait to solidify an image, the more variables you introduce that can make things go wrong.
Here is an example.
What's wrong with this? It's unexceptional, sure, but I want to focus on what we imagined when we read this and in what order.
If you're like me, you read this either as bare stage directions or a single shot of David that retroactively turned into a two-shot.
The former is boring, and the latter makes you distrust the writer.
Why? As the writer described David, it hinted at a more extended shot, solidifying a single of him in our head. But then... surprise! It's a medium two-shot.
You do not get credit for complicated sentences. Simplicity and clarity are better.
The better choice? Maybe something like this.
I prefer this because the first thing it does is establish an image, "David and Gretchen sit at a small table across from each other."