For now, just be patient and keep posting. You only have a short trailer up now, not even the first episode. That's way too early to expect a bunch of readers or to gauge how many people will be interested.
Also, I think it's safe to say that pretty much anybody who gets hundreds of subscribers within the first few days does so because they already had a significant reader-base somewhere else and are just migrating their comic to a new platform. It's extremely unusual to just explode in popularity from the beginning.
Regarding the comic itself, the art looks good and the aesthetics seem interesting, although the intro seems a little generic and vague to me. Also some of the text might be blurred too heavily, it's a little hard to read.