Steven Pressfield told James Altucher:
Advertising teaches you nobody wants to read your shit so you better make it immediately compelling.
He continues (paraphrased):
The other thing it teaches you is how to edit. The space has constraints you need to fit in. A 60-second ad goes by FAST.
People romanticize creativity as being willing to go outside the lines or put something magical onto a blank page.
The reality is, creative people get something done within pre-defined constraints of some sort.
The better you know the constraints, the more focused you can be on what you can do with whatever you’ve got.
If you’re writing from the standpoint of “nobody will want to read your shit so you’d better make it engaging,” you’re already of the pack.