1. Imply what the readers already suspect.
You'll find that a huge reason people continue to look towards a story is because the plot thickens and things escalate quickly. Now I'm not saying go overboard with every single plot point, because people want to have a sense of astonishment while reading comics/novels. Doing that will only heighten the experience people have with your comic/novel in a good way.
2. Steer clear from answering spoilery comments.
In this case, you could simply like someone's comment because they're starting to put the puzzle pieces together or tell them something so questionable, that they'll feel inclined to want to know more about the future of the plot.
3. Plant the seeds for said subtle themes right from the beginning.
This one is optional I feel. Instead of shoe-horning several ambitious arcs all in one episode, you can build invested interest by sugar-coating a theme whether small, large, or somewhere in between from your first few episodes/chapters. This gives you some flexibility when deciding if you want to go along with it or not. In this case, what I like to make an example of is romance. Seeing that there are quite a lot of romance comics and novels on Tapas, make a discreet gesture of two people blushing when they're around each other or getting upset if some else talks to them. Love triangles make things spicy as well
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