>>3133239Use both!
Tumblr is easy to start out with, even though it's dying the fanart/shipping community is still fairly busy. And people actually search through fanart/character tags.
For twitter, I think dedicated fanart accounts get the most attention. Like, make your icon and header whatever series you're drawing. Post art. Then follow/like/rt art and interact with other people in the same fandom. You need people to notice you to get any traction on twitter, otherwise you're posting into a void cuz the tagging system is kinda useless (unless its a meme tag like inktober or visiblewomen)