I know this is kind of a contentious practice but when I was first starting out with Unfamiliar I made a cute little thank you image I would post on subscriber's walls thanking them for following my comic. (its best it you type something personalized too so they know it's genuine and not spammy) I did that until I couldn't keep up anymore. But the main thing is just making sure you're improving your work all the time! The art, the story, the hook. Those things bring in subscribers more than advertising can. Remember, getting someone to look at your work is only step one, getting them to like it, get invested, subscribe, tell their friends, all that has to come from you and your hard work. Plus its more fun to think about your comic rather than boring analytics imo. >w<