There is a large reader base just within Tapas. One of the big ways people see your comic is from updating consistently. Each update (max once per day) puts you in the top of the "fresh" section. That combined with a fetching thumbnail gets you clicks, gets you eyeballs on your comic, and potentially gets you new followers.
But it takes time and patience.
Other things you can do are link to your comic in your forum profile. That way when you post in the forum, people here might check you out if they're curious, or as a way to get more information and better give better advice. You can also promote on social media like tumblr, twitter, etc. Then as you go, you might look into more ways to promote, cross promoting with other creators, paying for ads, etc etc.
There are lots of topics on these things, but hopefully that helps you getting started?
I don't think tagging the comic is currently very helpful, but it doesn't hurt to do so. I'm pretty sure tagging individual pages does nothing.