I was pretty good at taking tests.
My strategy was to sprint through the exam and rough-in answers as quickly as possible.
While I went, I flagged answers that I wasn't as confident in.
Then, I'd go back through and look at each flagged answer in more depth until I was confident in it.
This breadth-first approach allowed me to get to good enough as soon as possible and then tighten the result until the buzzer went off.
I wrote papers the same way.
First, I'd just barf out, free-association-style, 2x the number of pages required.
That means that if the buzzer went off before I improved it, I at least had a good-enough (though messy) result that technically cleared the bar.
Then, I'd iteratively go through the essay, tightening it:
Moving similar arguments next to each other.
Reducing duplication.
Moving arguments so they built on each other in a coherent order.
Cutting uninteresting observations.
Adding signposting and transitions.
Tweaking wording to be less confusing.
As I chiseled away the marble, I'd discover my thesis.
This strategy naturally focuses time on the things that can get incremental benefit, and allows you to juggle multiple things naturally.