In my longer pieces, especially my nonfiction, I am good at finding a theme or some kind of moral proposition/focus. I guess some larger point which makes my writing applicable to others without being preachy or overt. Also, I like the way I put words together, and the flow of my writing.
I'm really good at plagiarism. I'm a copy and paste artist, I tell you.
In all seriousness, I really don't know what I'm good at as far as the actual writing goes, I don't know if I'm any good at the writing part, but I really believe that some of the crazy ideas for poems I get in my head can be really stellar. As far as getting them onto paper with the right wording and hooks, I have no idea. I've put up two poems I've written, hopefully I'll find out what I'm good at or bad at soon enough.
In poetry, these days, I'm good at capturing "snapshots" or slices of emotion and imagery. In creative nonfiction, I'm good at being vulnerable enough, at letting my guard down enough, that other people can find bits of themselves in the vignettes I write.
I can't put it in brief so I'll put it in a slightly long exposition.
When I first came here on dA, my first entry was a fan-fiction fantasy blank verse style poem for "shadow of the collossus".
Immediately after that, I wrote a sci-fi alien specific prose, first person, stream of consciousness work called "the conquest of MUZTWA". in essence, that was my first novel series here on dA.
Then came "Vigillum" - third person fantasy prose writing with a JRR Tolkein, Lovecraft, and slightly Freudian/Jungian approach merged with ideologies and constructs inspired by w40k (not directly related, mind you. Just in terms of the cynical approach).
I started writing my poetry and short stories after that.
the shortest I've ever written is "Question" and the longest is "Mise un abime". the former was six words, and was straightforward. the latter was a mix of a rant merged with some form of a story... Apart from them;
My first poem was "A Desert Flower". Although having said that, I have written obscure poetic works as well: "Shadows in the Drapery", "My Inner Sanctum", "The Orchard of Spring", "Apoptosis"... among a notable few.
My old school works are "A Byron's Advice" and "Mistress" - the former is a tribute to Byron, while the latter was purely spur of the moment.
I've written free verse as well - "The Wolves" in particular. its about bullying.
moving on from there:
in terms of short stories, I'm a serious writer - I look into subjects that speak about... more or less human nature's personal side.
Works: "Glass House", "Trembling Hands", "Cold November", "The Dream I used to have", "Labyrinth", "Pipes", "A Perspective", "Look there".
That isn't to say I don't explore further. "The Origins of Squee and Nuu" was my funniest work to date; "Jubal's Terror" and "Jubal's End" are both interrelated works based on a fantasy theme; the "Orbit" series that I've written is my own philosophical take on life; "The door", "Romanticized Sahara", and "Sahara revisited" were my ideas about the year 2012; I once wrote an essay about Jude the Obscure by Thomas Hardy; "Dear Adult Me" was just a submission for that contest - its not exactly me, its just me playing along with a character.
My personal works, though, are just as serious: "Overcast Skies" was one of them. "Christmas means to me family", the occasional letter I've written.
I've written dialogue writing too: "tra le braccia dela morte e vita perche a vita e la morte" was my first, "You're a fool O Mcbrian" was the next, "Captain Ulmar Wenceslas Lockhart" was a complete play, "The Tale of Lucifer and Constance" was another dialogue driven poem.
Having said that, my most different works are "amor vincit omnia" and the "Krummvisiur Saga" which was a take on a fable based approach (and even in that saga, my approaches vary significantly - it comes out like a play for the most part).
I had someone compliment my dialogue once. I think I use way too much of it, personally, and don't use enough detail, but that's me. A teacher of mine also said once that my rhyming in poems was really good and apparently I use a lot of rhymes that are not exactly common and most don't think of.
Generally the only thing in writing I consider myself all that exceptionally good at is having my characters convey their emotions and feelings. I've never had anyone point it out, but I think I do a pretty good job at it.