"You can't learn to write in college" -- Ray Bradbury Interview
theparisreview.org
theparisreview.org
Filling pages is different from writing. The most frequent criticism he'd levy was "show, don't tell".
Why not 600 words? Doesn't a 300 word cap squeeze so hard that one is forced to respond with gimmicks? Can you link to any successful 300 word essays on-line, I would love to study them and see how the trick is done.
Sadly, I don't have any examples. It was a loooong time ago.
I think the 300-word cap was to force you to choose every word carefully.