I've had a lot of success with Twitter, but I have made an effort to use it to get comic readers.
Basically you want to be someone interesting to follow, so you have to post content of value. That can mean sharing tips and tricks, WIPs, funny jokes, interesting observations, etc. If you only post links, that isn't really valuable and you won't gain followers. You should be in the mindset of what you bring to others. Sometimes that can just be interaction. I personally post WIPs, a bit about myself, engage in hashtag discussion, but mostly I chat with other people, either on their posts or by replying when they talk with me.
Social media is all about putting yourself out there, even if you have great work no one is going to seek it out if they don't know about you. With the vast amount of content fighting for attention most people don't go clicking on random links, there has to be a driving factor. The art or synopsis is interesting, a friend recommended it, they saw the rough drawing and want to see how it turned out, they think you are interesting/passionate, etc.
I would suggest following some people on Twitter and seeing what you like and don't like about how they post. What gets you to unfollow? What gets you to interact? then emulate that. If you really want people to read your work you do have to invest time in marketing/social media, no one is going to do it for you.