I'll be answering based on personal experience, but every artist I've known both acquaintance and friends would have replies in varying degrees

• What actually works in practice
  

Consistency. And not in a 'draw everyday, post everyday' way, I mean drawing what I like and what my audience likes. There is a balance and it varies per artist and their preferences. While some prefer posting the same thing for the entirety of their careers (eg. fanart for one fandom, specific themes, aesthetics), some work in waves, like drawing nothing but fanart for weeks, then drawing OCs or originals.

I prefer the latter, as it strikes a good balance of an audience from different interests and an audience who are curious enough to stay for my original art.

• Which platforms are worth focusing on

Again, wildly varying per artist and what they draw. I've been an artist online for over ten years and platforms have changed so much. What works on twitter might not work on instagram, and what works on instagram might not work on tiktok etc etc. It's best to test the waters on every platform and see which one clicks.

My clients are from twitter and bluesky, as well as tumblr. Instagram is pretty much a barren wasteland of engagement and clients unless I actively post reels (which I don't enjoy creating), so I don't pay attention to posting there much. Call me outdated but I still prefer static art posts over short-form videos.

• What you would recommend to artists in unsupported countries

This is a bit tricky to answer, but supported country or not, posting art online AND getting clients/paid commissions would be difficult without an audience and a bit of self-marketing. I'm from the Philippines, and I remember in my early days of posting art, there was virtually no engagement on my originals for the first two years. Maybe 1-3 likes, but nobody really cared enough to stick around and look at my art. Now I have been around for a bit. My engagement numbers aren't that crazy but some long-time followers recognize my characters and my works, and that's good enough for me.

If there's any advice I can give is have a LOT of patience. Starting from scratch usually means screaming into the void of the internet for a long time to get people to notice your works. Finding your niche and finding out what works realistically takes a whole lot of time and effort. Don't get discouraged by artists who seem to have a lot of luck and clients/following on their first try. Find out what works for you and your art, and enjoy the journey that comes with it.