For example the better (while old) Websters Revised only has these two entries for "writings":
3. A book; any written composition; a pamphlet; as the writings of Addison.
...
5. Writings, plu. conveyances of lands; deeds; or any official papers.
It specifically mentions that writings are more formal and pretty spot on for how we use the word.TLDR; use this http://machaut.uchicago.edu/websters 1913 websters dictionary rather than the newer, while correct, dictionaries that don't capture vernacual. It's a shame a state of our dictionaries.
"go with my gut" rather than "guts", and I'd probably phrase it as "...try to go with my gut more next time".
"Oftentimes" sounds unnatural, not wrong but archaic; "Often" sounds more natural there.
"mental lexicon" is singular, but you've said "a lot more of them"; should probably be "a lot more of it". The opening of that sentence sounds a bit clipped; I might say "I believe the mental lexicon..." though that doesn't sound perfect either.
"writings" definitely sounds wrong for a collection of posts here; when you're talking about "the writings of x" it implies something more formal. I probably would've said "posts" or the like, but "writing" fits.
> So, dear native speakers, which is more appropriate in my use in the GP comment? writings or writing? :-)
Definitely "writing". An author might refer to books that he wrote as "writings", but it would sound odd (or even pretentious) for anyone to refer to their posts on HN that way. Besides, you're not really asking about your previous posts, but about your ability to write English in general. So it's your "writing" (in general) rather than your "writings" (the particular posts you've made here).
'Writings' is an interesting case. I believe mental lexicon is a lot harder for non-natives to grasp, simply because there are a lot more of them and English does not always treat them consistently. For example, I thought that a collection of written work is plural, while apparently you consider it a collection or an abstract object, and therefore used without an article and cannot in general be in the plural form.
However, this is what I found using Google 'define writing':
So, dear native speakers, which is more appropriate in my use in the GP comment? writings or writing? :-)