"...nervous people worrying about their language write worse than relaxed people enjoying their language." (Geoffrey Pullum, hat tip: Jonathan Mayhew)
Many people think that their writing problems stem from their ignorance of the rules of writing. Whether they think it's their understanding of the grammar of an English sentence or the rhetoric of a journal article that is inadequate, they believe that there is something important about writing that they don't know, and if they were only let in on the secret they would write more effectively. I never miss an opportunity to push back on this idea when I talk to writers.
If you're not writing as well as you'd like, it's because you don't write often enough (or haven't been doing it long enough). The only thing that will really make you a better writer is time spent writing. Don't let someone else's list of grammatical "pet peeves" cow you into not writing a sentence you think clearly expresses your views. (And please don't try to bond with me about how much you "hate it when...") Do, of course, listen to what other people say about your writing and, if you already respect their opinion, follow their suggestions to see if it improves your text. But you are the final authority on whether an improvement has been made. You are the author.
Andrew Gelman has some good advice about writing on his blog. The good thing about this advice is that it emerges from a reading of actual work done. He's not just cherry picking examples of bad writing from the newspaper and elevating his disgust into a universal rule that only the bad people who can't write would break. He's not trying to scare people away from writing badly, he's showing them how to write better.
Finally, in honor of the coming Zombie apocalypse of pompous-poppycock grammar rules let me take you back to my youth in Canada with this catchy little song by the Odds: "Eat My Brain.".