Lots of time management, learning what posts are the most effective on each site, and how much time you should truly dedicate to each platform. Sites where I have a low amount of followers, I spend a little less time there and use it as, mostly, a firing ground. I still remember not to completely abuse these profiles by also mixing in tutorials and other thoughtful posts that I've made on other platforms. They're kind of a mirror social media platform for my other more popular social media accounts. There are also sites that can help post on multiple sites like hootsuit or IFTTT (if that than this). These sites can help save some time.
Also I find that it's important to comment and share other people's posts. I have a quota of commenting/sharing at least 5 posts from the other people I follow on these sites, and always share they're new comic page posts to spread that news. That helps build a friendship with other artists/people on the site and they'll help you back by commenting/sharing your posts. So many times, people post things and it goes unnoticed or just no engagements what so ever. We all know how much that sucks, especially if the post is something we feel strongly about. So I find it's a good practice to do my part in ending that. Instead of zipping past a post I mildly liked, I'll respond to it and make a friend.
And just to restate it, always help reshare other artist's new comic update posts. Us artists have to stick together, ya know. Together, in a group, if we all do this, we become like a megaphone and help all of us reach a wider audience for our comics. 
