It's easy to take any writing assignment and improve it by an order of magnitude.
Just sleep on it.
When you've finished a draft of something, whether it's a book chapter or a blog post, walk away from the work. Leave it and take a fresh look at it tomorrow morning.
When you stare at the same text all day long, all sorts of problems crop up. You get too close to the work. You start to develop typo blindness. You get bogged down in things like phrasing and word choice and lose sight of the overall flow of the piece.
But when you step away and come back to a writing task the next day, you'll have fresh eyes, a fresh mind, and you'll have established a mental distance from the work that will allow you to judge it objectively.
Suddenly, typos stand out rather than blend in. Grammatical errors leap off the page rather than hide. And you'll easily hunt down and exterminate awkward phrasing and poorly constructed sentences.
Of course this writing strategy fails utterly if you wait until the last minute to do a writing task. Which is another reason it's so important to keep a queue of completed work in the can at all times.