I have an 80% rule when writing. It is the supporting caveat to all my other writing rules. You could say, though I call them all rules, that it turns them more into guidelines.
Because the 80% rule is that I only follow all my other rules 80% of the time.
The thing is, writing is not the domain of the perfectionist. You will never do everything in any story 100% of the time. You will use adverbs. You will need boring dialog tags. You’ll need an extra “that” to make the sentence flow or a passive verb just to get the point across. I will absolutely have fragment sentences (ask my editor).
Copy editing is perhaps more for perfectionists but even then, I’m going to hold mine to the 80% rule too (it’s call artistic license – fun story about the rounds I went with my editor for Tattered Heart).
We don’t like certain pieces of our language because they’re boring or functional but they exist because sometimes you require the function they provide.
So, let them. Let yourself misuse a comma. Let yourself just say what you need to say in the simplest way possible. Adverbs and all.
Because if you can improve 80% of the things then you’ll have an exceptionally better book. And you’ll give yourself the freedom to write what you need to write without the stress of having to follow all the rules.