Okay, here are a few things to keep in mind.
You're always going to have a LOT more views than subscribers. This is okay, and happens to everyone.
On the contrary, it IS that hard! I have literally hundreds of thousands more views than I have subscribers - it's the nature of the game, honestly.
How long have you been posting your comic? I clicked on your forum-profile, and it says you joined the forums 43 minutes ago. I'm assuming you only just started posting your comic? You need to be patient to get anywhere in webcomics; there are no overnight successes. When you see a comic with thousands of subscribers? Those subs took a long time getting there. Either the comic has been running on Tapastic for a long time, or the creator(s) had fans on other platforms who followed them here, too.
How to gain subscribers, a handy guide:
1. Post your comic as often as you can, and as regularly as you can.
2. Be as active in responding to comments as you can; people like seeing creators who engage with their fans.
3. Promote your comic on your social media-accounts. Twitter has a very active and friendly webcomics-community, with the weekly #ComicBookHour and #webcomicchat events, so that's a good place to start! If you use Facebook or Instagram or Tumblr, use those places to promote yourself as well!
4. Be active on Tapastic. Posting in the forums is good, but you should a.) not spam links to your comic in threads where it isn't relevant, and b.) you need to manually add the link to your comic to your forum-profile, since Tapastic doesn't automatically connect the two.
4.b. Being active on Tapastic also means finding comics you like, and commenting and engaging with them. DON'T SUBSCRIBE TO COMICS JUST TO MAKE SOMEONE SUBSCRIBE TO YOU! But do find comics you enjoy, and subscribe and comment. It is all part of establishing connections and making friends.
Also, if there are community events, like the Tapastic Winter Fest from last year, try to participate in those!
5. Be patient, and keep making comics. You will not be an overnight success. NO ONE is an overnight success. Look back at your comics and number of subscribers a year from now, and I promise they will be a lot different!