Don't send an article to a journal and leave in sub-headings like "5.1, 5.2" etc... The reviewer is going to know that this is chapter 5 of your dissertation and you simply haven't bothered to change those headings. Ouch.
Don't use the passive voice as a simple default mode. It shouldn't be your automatic, unthought-out choice.
Don't save your worst writing for the key paragraph in which you are explaining what the article is about.
Don't call your own work "groundbreaking." (Well, you can do it if you are writing jacket-copy for your own book, but don't do it in the book itself.) It just doesn't sound good.
You can feel good. You can also feel well (being the opposite of sick, not the adverb form of good), but you can't feel badly or horribly. That's a hyper-correction. I winced when Donald Trump corrected Cindy Lauper and she accepted the hyper-correction of "I feel bad" to "I feel badly." At this point, though, the hypercorrection is itself a colloquialism accepted by many speakers of English, so I guess you can feel "badly" if you really want to.
Don't use the word thusly in formal writing. Thus is already an adverb and thusly is a jocular expression that only belongs in certain context. Well, I hate it even where it does belong.