ahh what a fun question!!! i'm always so glad to hear from other artists, i really hope you find the courage to start posting stuff and have a super enjoyable time with it regardless :) i will have to say that my only experience with this is in the nsfw skiz community. i'd honestly have no clue how to tackle this in the general art community, which i do want to make an account for eventually... but i am assuming a lot of it is the same general idea tbh!! so hopefully my answer will be useful no matter where you decide to post your art <3

now i'm assuming your question isn't literally just "how to post art" but also "how to establish yourself as an artist on twt", so i will give some pointers for both. sorry if that's actually not what you meant sdkjhsdf in that case please just do not perceive me in the second half of this answer. anyway here's some of what i did :)

firstly, from a purely technical standpoint, it's useful to consider image dimensions when you upload art; if your image is too tall or wide or if you post multiple pictures, twt will crop the images, and it might affect the way people perceive the art you worked so hard on! if you wanna avoid this, i recommend looking up the twt image dimensions and keeping those in mind as ratio limits! personally i usually use a 3000x4000px canvas with 300dpi for my digital art. i honestly have no particular reason for those dimensions other than it's easy to remember, pretty nice to look at (imo), and it fits in the feed without getting cropped :') but you really don't need the canvas to be this big at all!! twt upload quality will eat a lot of the detail anyway... definitely try to stick with 300dpi though, if you can! it helps prevent grainy/blurry textures.

if you wanna upload traditional art, use the best camera you have and make sure you photograph it in bright, preferably natural light, and don't be afraid to play with the light levels/saturation etc in your phone's picture editor before you upload! traditional art looks wonderful irl but if it isn't photographed well it can really take away from its beauty, so it's worth it to put in the effort and make it appear just as beautiful on screen :)

for captions, i personally like to keep them pretty minimal (just a title or short description; it helps to make clear that you're the one who made this). i used to write little stories or anecdotes there, describing my process or what inspired me, but i now find that i prefer to keep the focus on the art itself, it looks nicer that way to me. if i wanna add more info i'll just reply directly to the post so people can still easily see it! also, generally people appreciate it if you add a sensitivity filter when you post explicit content, or some content warnings if your art contains potentially triggering things: certain kinks, gore, stuff like that... this is all very much up to you though! i personally do think about content warnings whenever i post art but i don't put one if there's only a very small amount of blood, for example... but i know some others would definitely still do that! i can't tell you what the "right" way to act is there, it's just about how you want to present you art i think.

OH and also!!! don't forget to put your name, signature or @ somewhere on the image! i used to put my twt handle on there but then i figured i didnt actually want people from outside twitter to find my nsfw account through reposts on pinterest and stuff like that, so i now simply use my name. but when i eventually make my general art account i'll definitely put my full @ on there every time :)

ok!!! that's all done. sorry this is already so incredibly wordy, this is who i am <3 anyway onto the establishing yourself... first important thing is that you gotta draw what you're actually interested in drawing. purely drawing to follow trends or get noticed won't get you anywhere in the long run bc it will deplete your creative energy in no time!! so yeah, try to figure out what you'd like to draw and what represents you as a person and an artist (for now!! this can of course change over time- in fact, i'd consider that very likely). it will keep your motivation up and it will also show people what to expect from you!

one thing i also definitely recommend for that (but also. in general) is to make your account layout recognizable as belonging to an artist... using your own art for your icon and header will help a lot, putting something in your bio about how you make art does as well, and i also think actually pinning some of your art (either in a thread or just pinning your most recent art that you're proud of, for example) really helps too! that way if someone checks out your profile they can immediately see what you do.

now, in a normal social media setting i'd assume you use relevant keywords or tags to make sure the right people can find you (that's what i've seen other artists do at least), but within the nsfw kpop community it's a bit tricky because it's the norm to actually actively censor words and avoid tags. if this is also where you intend to post, this means that if you want people to find your art, you'll have to find other ways to make them notice!

for that, there's multiple things you can do. simply interacting with other people you like is already a big help; honestly, just try to make friends like you usually would. engage with art you find interesting, comment on people's posts, join conversations if you think you have something fun to contribute... of course don't try to make friends with the goal of having them retweet your art please jkshdf but yeah just! making yourself known in the community by becoming an actual part of the community usually helps a lot!

another option is to join art challenges that interest you! sometimes people will have a dtiys you can join, sometimes there's seasonal events... usually with things like these you can tag the accounts involved and they might retweet your art for you! (i'm staring very guiltily at the st4ytist event twitter right now bc i'm aware me and the other mod have completely left it behind because we've been too busy but... that would have been a nice way to join in and get noticed. i'm sorry!!! maybe one day i'll pick it back up again, i did really enjoy the events we hosted 🥺) also i know i said before to not purely follow trends when you draw but... once in a while it can't hurt to hop on a trend you find fun :) i find that my art usually seems to get more interactions if it's kind of "topical" (aka related to a recent picture/event). ...or if it's kind of horny. people seem to really like that too fkjshdf

and of course lastly, you can make art directly for other people. now this is tricky bc there is a fine line to walk here; please don't just make art for people because you want them to notice and love you and retweet your art for you. that's not how this works and it will probably only cause disappointment! instead, try to only draw things you would feel good about drawing even if the person you're drawing it for doesn't even notice it at all. for example, if there's a fanfic you really hold dear to your heart, it'll be great inspiration anyway, so why not make some fanart for it! again, don't badger the author to promote you, but definitely make sure to tag them or send it to them and just let them know how they inspired you, they'll for sure appreciate that :) and even if they don't really seem to care for the art itself, you posting it will make it easier for other people who loved that fic to find you, which has the added benefit of finding new friends with shared interests!! also, i see plenty of people share brainworms on the timeline, or even literal requests for artists to draw a certain thing; if there's ever something that actually sparks your interest, please go for it! qrt them with your drawing and there you go, you participated!

honestly tho, all in all i think the most important part of posting art on twt is realizing you cant force people to like or engage with your art, so it's best to just draw what makes you happy and engage with what interests you; that way the people who like your art and share your interests will naturally gravitate towards you eventually :)

btw once you have established yourself somewhat, you can try to focus a bit more on active "audience participation" (if you want! i know not every artist is interested in this, but i personally really like feeling actively part of the community so i do try to focus on this). for example, you can start asking your followers if they have requests or let them vote in polls, you can make your own challenges that people can participate in, you can share wips, timelapses or other process insights to show more about your work methods, stuff like that! although of course it's also completely fine to just come online, post your art and disappear into a mysterious mist!! it's all about what you want from your experience here..

i really hope i was able to provide some guidance for you and i'm sorry if i was a bit too wordy or overstepped in assuming what you wanted to know about!! thank you so much for the nice compliment and also the trust you had in me to ask me this question :')) hoping to see your art pop up sometime soon on my tl!! <3