Getting attention on Novels here is...hard to say the least. I mean its hard with the actual comics unless you get featured in someway but novels? Yeah I've been posting for about 3 months too, did several kinds of advertisement and promotions and throughout it all, I am still (at the time of this post) below 20 subs.
And I know it's not just me but it's like, wow it can be slow. I'm hoping to reach 25 subs by April if possible and you know what? I'm the lucky one. There are novels up there that haven't even hit the double digits yet in readers. The only thing I can really say is, keel posting, keep advertising and keep promoting.
For myself, I'm constantly posting (mainly because I have a good build up of pages) and I tried to advertise and promote whenever I can. I also put illustrations within my work, giving it a unique feel that many other Novels lack. I do wish more genres for novels were added though. I have mine under "Fantasy" but if I could, I'd put it under an "Action" genre.
As with anything on Tapas, but especially novels, you have to be diligent. If I reach 25 subs myself, I'll be ecstatic because I know its a milestone many others have yet to reach as well. Promote and advertise and if possible, show off your work. As I said, I draw illustrations with my novel to help it stand out. Maybe there's a way for you to also catch your reader's eyes.