"Getting Subs" is this weird combination of pitching your work well, being persistent and consistent, having good work, engaging folks wherever you can, and then just happening to be seen by the right people.
So, how do you get more subs? If you engage people on social media, will you get more subs? Well...... building a presence there and making connections can lead to more subs down the road. If you make your comic's art or writing better, will that get more subs? Same thing -- it won't immediately make your subs shoot up, but it'll mean that eventually, when people run across your comic, they'll be more likely to get interested. If you just keep updating consistently for a long time, will that be what gets you more subs? Well, that's part of it, but it doesn't mean that people will flock to you just because you exist.
That's why this is tough question to answer, and why the answer ends up being "just keep going!" It's sort of, all of these things put together, over time, pay off in the long term. So there's nothing anybody can tell you to do that will make your subs go up RIGHT NOW -- it's just a matter of, keep finding new places to connect with others, keep watching and learning from other creators, keep creating new work, and keep improving!