Yep, I'm going to echo @JohnVincent and @Vanesalisa, replying back to commenters is very important even in the beginning when you're not receiving many comments. And when you can/where it makes sense, try to reply back with more than a 1 word reply. Perhaps start to start a conversation? I've had a few emotional pages where readers could relate to the situation and then talked about it with me in the comments. Stuff like that is when you start building a friendship with readers.
Also Q&A events where readers ask comic characters a question and you answer it in a comic is fun for everyone. Art request livestreams is another one. Maybe tipper rewards?
It does take time to build up a readership and then coming across as engaging also takes a lot of work, especially when shy. Just take it in strides. Each successful interaction will help boost your confidence making it easier to engage. For me, sometime I wait a few hours before responding to comments just because it takes building up that confidence and figuring out what to say.
