I mean, polls and such can be helpful. Letting us know whats going on with you also helps. I tend to personally give my commissioners my telegram, partially bc it helps with showing someone the first draft, and on and on. Whatever you feel comfortable with, honestly.

Tbh I have found the only way to connect with people is to speak to them first.
Personally, I comment on journals, but I don't comment on artwork unless I feel I can improve them. I mostly try to find people relatively new to the site, and encourage them. That hasn't really worked so far in establishing consistent communication, but I still would like to pretend it helps them.

Either way, good luck dude. Keep in mind a lot of people are on here solely to market their art, so try engaging them with that specifically. Focus on what makes them stand out from everything else on here (their use of settings, realism/cartoonism, influences, etc).
If you ever want to exchange comments on art, I'd be all for that, by the way.