The one I have better luck getting comm is twitter and reddit, and I only got one via instagram so far (some more if you count those that ghost me). Twitter and reddit have a whole lot of competitors and so the only thing you can do is to promote the hell out of your commission everyday, and keep a tab on the search page for people looking for commission. I mean, 9 out of 10 of my reply and twit is basically me trying to look for commission. ;v;