it seems to be in this order:
1st as @graveweaver said, thumbnail. If your thumbnail isn't effective no one will even click on to open up your comic. There's a reason bl creators put a bl tag on their thumb, it helps them attract their target audience.
2nd is what @Kimoisempai said. your opening and art need to make a good impression.
3rd is your current sub count/hearts. if you manage to break a thousand you get an icon, and basic mob mentality will get people to check out your comic
after that, its a matter of having a decent story to maintain your subs.
if you dont have these aspects, you'll need to rely on being recommended by either other creators, or the platform itself. if you do have these aspects you may still need to rely on others recommending you. The site has a lot of comics, sometimes its just hard to be seen.